Low Emission Zone: Sofia’s Experience

Prepared following the working visit of a delegation from Almaty to Sofia, Bulgaria, held on 6–10 July 2026.

Delegation: representatives of the Almaty Air Initiative PF, the Almaty Parking Municipal State Enterprise on the Right of Economic Management, Eco Almaty LLP, as well as members of the working group responsible for developing and implementing the Rules for the Protection of Atmospheric Air of Almaty.

Purpose of the visit was to study Sofia’s practical experience in implementing a low emission zone (institutional, technical and communications aspects of implementation), in order to develop recommendations under the Rules for Protection of Atmospheric Air and assess the possibility of applying successful practices in Almaty.

Almaty Air Initiative expresses appreciation to all representatives of the City of Sofia for the productive meetings and sharing experience with our delegation, and for their openness in discussing not only the achievements of the reform but also the practical challenges encountered in its implementation. 

We would like to thank:

• Vasil Terziev, Mayor of Sofia, and his team;
• Stolichna Obshtina (Sofia Municipality) for hosting the delegation and organizing the meetings;
• The Climate, Energy and Air Directorate (Дирекция „Климат, енергия и въздух”), the municipal department responsible for the low emission zone;
• The Transport Directorate (Дирекция „Транспорт”);
• The Spasi Sofia (Спаси София) party;
• The Vitosha District Administration (Районна администрация „Витоша”);
• Air for Health, (“Sdruzhenie za zdravie” a medical expert association);
• The Center for the Study of Democracy (Център за изследване на демокрацията, CSD), a think tank involved in developing the regulatory framework.

We would also like to express our special personal gratitude to Nadezhda Gantcheva of the Center for the Study of Democracy (Център за изследване на демокрацията) for coordinating the meetings and providing expert support; to Plamena Terziradeva, a member of the Sofia Municipal Council representing Save Sofia (Столичен общински съвет, «Спаси София»), for her personal assistance in establishing contacts with the city administration; and to the Embassy of the Republic of Kazakhstan in the Republic of Bulgaria for its support in organizing the visit.

Executive Summary

The experience of Sofia, the capital of Bulgaria, is particularly relevant to Almaty: both cities are located in mountain basins, experience winter temperature inversions, have ageing vehicle fleets, and face a significant contribution from household heating to air pollution. Sofia became the first city in Eastern Europe to introduce a low emission zone (LEZ) that simultaneously restricts the movement of the most polluting vehicles and the use of coal and firewood for heating.

The main conclusion from the visit is that the complexity of the reform lies not so much in developing the rules as in enforcing them. Sofia developed a relatively well-designed framework for the zone but encountered difficulties with the collection of fines, inter-agency data sharing, exemptions, insufficient communication, and a weak impact evaluating system.

Separate lesson concerns political leadership. The reform in Sofia resulted from a court ruling rather than as an initiative of the city authorities. This gave the reform legal resilience, but at the outset it lacked strong political ownership. For Almaty, the opposite conclusion is important: a reform of this kind requires clear leadership from the city’s top administration from the very beginning, together with unified accountability for the outcome.

At the same time, Sofia benefits from substantial external support. European Union directives establish a binding air-quality framework, while EU programmes help finance the costly transition. In particular, European funding made it possible to replace approximately 20,000 heating devices free of charge. For Almaty, where no comparable supranational system of obligations and financing exists, sources of funding and mechanisms for monitoring implementation will need to be established independently.

Coalition in support of the reform is equally important. Sofia’s experience demonstrated that restrictions cannot be implemented sustainably through administrative instruments alone. Doctors and medical associations proved to be among the most effective allies: people tend to place greater trust in information about the health impacts of pollution when it is communicated by medical experts rather than politicians. For Almaty, doctors, independent experts and residents can become an important source of public support for the reform.

Sofia’s experience also shows that restrictions must be accompanied by alternatives and social support. In the heating sector, the principal instrument was not fines but subsidized replacement of heating equipment. In the transport sector, restrictions were introduced after the development of the metro and other transport alternatives. Moreover, even before fines were fully enforced, the average daily number of detected vehicles in the lowest environmental category fell from approximately 20,000 vehicles per day before the zone was launched in December 2024 to around 1,300–1,400 violations, representing a reduction of approximately 93%. This demonstrates the importance of communication and the expectation of sanctions.

For Almaty, preparations should begin before restrictions are introduced, including an inventory of pollution sources, baseline measurements, inter-agency data exchange, a functioning administrative system, the formation of a coalition of supporters, and the provision of viable alternatives for residents. All of this requires political leadership at the highest level of the city administration, the enforcement mechanism must not only be designed before the reform is launched but must also be capable of being adapted in response to residents’ feedback and public perceptions of the reform.

Sofia’s key lesson for Almaty: The right to impose restrictions must be earned. Restrictions should be introduced with due regard to infrastructure constraints and only after the city has provided genuine alternatives: an affordable transition to clean heating for households using solid fuels and well-developed public transport for drivers. The zone itself should be introduced gradually, beginning with information and notifications rather than sanctions.

1. Introduction

Sofia became the first city in Eastern Europe to introduce a Low Emission Zone (LEZ). The resolution establishing the zone was adopted in December 2023. Defining feature of Sofia’s model is that it covers not only road transport but also household heating with solid fuels. (Within the zone, the use of coal and firewood for residential heating is prohibited). At the time of its introduction, this combination had no direct equivalent elsewhere in Europe.

Sofia’s case is of greater practical relevance to Almaty than the experience of Western European cities because of the combination of comparable starting conditions.

Similar physical and geographical conditions. Sofia is located in a mountain basin and is subject to persistent winter temperature inversions. According to participants in the meetings, these occur for approximately 20–40 days during the heating season and trap pollutants close to the ground. This is directly comparable to Almaty’s climatic conditions.

Similar vehicle fleet structure. The average age of vehicles in the country is approximately 16 years. For many years, Bulgaria served as an end market for used vehicles from Western Europe. Until recently, there were no restrictions in the country even on vehicles meeting Euro 0 and Euro 1 emission standards. 

Implementation of the reform amid institutional instability. The reform was implemented against a backdrop of frequent changes in national governments and strained relations between the city administration and the municipal council. This makes Sofia’s experience relevant for assessing the resilience of environmental policy in an unstable political environment, unlike the experience of cities with a long-term horizon of continuous planning.

The general conclusion reached independently by almost all participants in the meetings can be summarized as follows: the conceptual and technical architecture of the zone has been developed to a satisfactory level, while the main challenges lie in implementation, namely ensuring the inevitability of enforcement, establishing inter-agency data exchange, and communicating with the public.

2. Air Pollution Profile in Sofia

The structure of air pollution in Sofia is determined by two principal sources, and the relationship between them has shaped the city’s overall policy.

Household heating is the main source of particulate matter during the winter period. It is particularly noteworthy that, at the outset of the reform, Sofia Municipality carried out a targeted inventory of the private residential sector: by 2020, a door-to-door survey covering a sample of 5,990 households had been conducted to determine the types of fuel used for heating. According to the survey results: 48,725 households used firewood, 12,181 households used coal, 19,313 households used pellets, 19,541 households used gas (excluding households using electricity and district heating). This preparatory step, measuring the structure of household heating before introducing restrictions, represents sound methodological practice. It provides an address-level database for equipment replacement programmes and the mapping of vulnerable households, as well as a baseline for subsequent impact assessment.

These data also provide a more precise picture: firewood, rather than coal, is the main solid fuel used in Sofia. Only around 12,000 households use coal for heating, compared with nearly 49,000 households using firewood. 

Road transport is the main source of nitrogen dioxide. Approximately one million vehicles are registered in the city; a significant additional burden is created by commuter traffic from satellite towns, particularly in the absence of a well-developed suburban rail survice. As a third and underestimated source of particulate matter, participants identified the resuspension of road dust, associated with unimproved roadsides, construction sites, and the quality of street cleaning.

Industry has now been almost entirely eliminated from the structure of major pollution sources. The closure of the large Kremikovtsi steelworks around two decades ago significantly improved background air-quality indicators, while the city’s heat generation system has been converted to gas. This is an important difference from Almaty, where coal-fired heat and power generation remains a significant independent source of pollution.

The overall trend is positive: according to the data presented, PM10 concentrations have decreased by 40–60% compared with 2018 levels, when concentrations were approximately 50–60 μg/m³. At the same time, the statistics have a structural weakness discussed in Section 6: the monitoring infrastructure available to measure the actual impact of the policy itself remains limited.

3. The Court as a Driver of Reform: From Litigation to a Low Emission Zone

A defining feature of the Sofia case, which shaped the subsequent logic of the reform, is how the reform originated. As representatives of the expert community explained during the meetings, the low emission zone arose as a consequence of litigation. In 2018, specialized non-governmental organizations obtained a court ruling requiring the city administration to adopt a programme of measures to improve air quality. The introduction of the zone became part of the implementation of that ruling.

This circumstance partly explains the dual nature of the reform. On the one hand, it has a degree of resilience because it is based on a court order and is not entirely dependent on the prevailing political environment. On the other hand, from the outset it lacked strong political ownership: the administration had to implement a measure that it had not itself initiated.

The implementation timeline, reconstructed from participants’ accounts, can be divided into three stages. The first year following adoption of the resolution was largely nominal: the zone existed legally, but the public had not yet developed a clear understanding of it. The second year functioned as a testing period: the zone was formally in operation and enforcement cameras were functioning, but the fine collection system was not. As acknowledged during the meeting with municipal council members, the practical effect was close to zero. The mechanism only began to function in the third year.

This leads to an important conclusion for planning in Almaty: the period between adoption of a regulatory act and the policy becoming fully operational may apparently take two to three years, and this is not a country-specific phenomenon. The key question is whether this period will be used for pre-launch preparation or for remedying shortcomings after implementation.

4. Design of the Low Emission Zone (LEZ)

4.1. Transport Component

The zone is organized around two nested perimeters. The inner perimeter, or “small ring,” covers the historic city center and has an area of approximately 3.5 km², representing around 0.7% of the city’s total area. Automatic number plate recognition cameras are installed at entry points. The outer perimeter, or “large ring,” is five times larger than the inner perimeter and covers approximately 17 km².

Figure 1. Map of Sofia’s Low Emission Zones.

Restrictions were introduced in stages: initially, vehicles in the oldest environmental category, (Eco Category 1), were prohibited within the inner perimeter, (inside the green ring shown in Figure 1), the restrictions were subsequently extended to the next category (Eco Category 2), within the small ring, and to Eco Category 1 vehicles within the outer perimeter, (inside the blue ring). The major roads forming the boundaries of the perimeters are excluded from the restricted zone, allowing through traffic to continue. In addition, before the zone was launched, the bypass road was widened from two lanes to three, with one lane designated for public transport, in order to provide an alternative route.

The municipality adopted three design decisions that warrant separate consideration.

Prohibition-and-fine model rather than an entry charge. Sofia’s zone is based not on an entry fee but on a complete ban on vehicles in the most polluting categories, with a fine imposed for each crossing of the zone boundary. This is a fundamental choice, the consequences of which became apparent during implementation (see Section 5): imposing a fine requires a separate administrative procedure for each individual violation, whereas an entry charge could be collected automatically using the already established logic of the paid parking system. During the meetings, the expert organization involved in drafting the regulatory framework explicitly recommended moving to an entry-charge model, similar to paid parking and the commonly used approach whereby, instead of fining a violator, a small fee is charged to every vehicle entering the zone. Such a model would eliminate both the technical challenge of identifying the vehicle owner and the legal vulnerability associated with enforcing fines. 

Seasonal Operation. The zone operates for three months, from 1 December through the end of February, whereas the heating season begins in October. This was the only design element on which there was near-complete consensus during the meetings, from city leadership to the opposition: seasonality is regarded as a flaw that should be corrected, at a minimum by extending the zone’s operation to cover the entire heating season and, in the longer term, by moving toward year-round operation. At the same time, the discussions indirectly suggested that the limited duration of the restrictions partly explains the absence of organized public resistance: residents tend to perceive a restriction with a clearly defined end date as more tolerable. Seasonality therefore represents both a weakness in terms of effectiveness and a factor supporting social acceptability. This trade-off should be designed consciously.

Exemption System. Residents registered within the zone who hold a parking permit are exempt from the restrictions regardless of the environmental category of their vehicle. As noted during the meetings, this resulted in manipulation of residential registration in order to obtain the right to enter the zone. In retrospect, the city leadership’s position on this issue is clear: it is preferable to abandon a system of individual exemptions in favor of a free transitional period for certain categories with a predetermined end date, because any exemption list creates incentives for circumvention.

Throughout the meetings, the city leadership consistently emphasized a phased approach to introducing restrictions: begin with a limited perimeter, test assumptions within it, and expand the zone as experience is accumulated. This approach is regarded as a means of reducing political risks and improving the quality of subsequent decisions.

4.2. Monitoring and Enforcement System

One of the most valuable observations from the visit concerns the gap between how the low emission zone appears in official documents and analytical materials and how it actually operates in practice. Implementation details, particularly the mechanics of actual fine collection, are rarely documented in public reports and are almost never discussed in case studies, even though they largely determine the real effectiveness of the measure. The opportunity to examine these details through direct discussions with several stakeholders was one of the main outcomes of the visit.

When asked whether fines are actually collected from those violating the zone restrictions, participants gave answers that at first appeared contradictory, although each of them was accurate. At the meeting with municipal council members, it was stated that the system was operational and violations were being processed. A representative of the district administration noted that actual collection of fines was almost nonexistent in practice. The Transport Department described the system as functioning, referring to the established range of fines and the indirect consequences for non-payment. The expert organization involved in drafting the regulatory texts reconciled these perspectives: all of the descriptions were accurate. Violations are indeed recorded, and fine amounts are established, but at the current stage the city administration does not, in practice, complete the enforcement process through to actual payment. 

The mechanics behind this limitation were examined in detail during the meetings. Issuing a fine requires a sequence of procedural steps: photographic evidence, preparation of an administrative act, signature by an authorized official, involvement of the police, and personal delivery of a paper notice to the vehicle owner. At the same time, the city administration does not have direct access to the database of vehicle owners, which is maintained by the internal affairs authorities. According to the information provided, preparation of a single administrative act takes approximately 15 days. During that period, the same violator may enter the zone repeatedly, while only one enforcement action may be formally processed. Judicial appeals against relatively small fines make their administration economically inefficient for the city. Eliminating these constraints requires amendments to the relevant regulations, which had not yet been adopted at the time of the delegation’s visit.

These procedural constraints are compounded by the political and economic context highlighted during the meetings: because the oldest vehicles are predominantly owned by lower-income residents, no level of government is eager to be the first to initiate full-scale enforcement. This caution is understandable and, to some extent, justified, but it also keeps the system in an intermediate state.

Importantly, even in this intermediate state, the zone is producing results. According to Sofia Municipality, before the restrictions were introduced, approximately 20,000 vehicles in the lowest environmental category (Eco Category 1), travelled within the zone each day. During the first seven days of the restrictions, from 1 to 7 December 2024, an average of approximately 3,700 such vehicles per day were recorded. By the end of the first week, the daily number of violations had fallen by approximately 30%. By January 2025, the municipality reported around 2,000 violators per day, and by February 2026 the figure had fallen to approximately 1,300–1,400. The number of the most polluting vehicles entering the city center therefore declined consistently by approximately 93% over three years, against a backdrop of public information campaigns, automated detection and notification, and before full-scale collection of fines had begun. At the same time, as city officials noted, behavioral change based on the expectation of punishment has limited durability. Sustaining the result over the longer term requires the certainty of enforcement.

As a target model for administering and collecting fines for LEZ violations, stakeholders described a system involving automatic notification and billing at the time a violation is detected, combined with simplified payment, with the Urban Mobility Center, which manages the paid parking system, potentially acting as the operator.

In Almaty, the corresponding electronic administration infrastructure has already been tested through the paid parking system, making it possible to establish a complete chain from detection to billing and payment collection from the very launch of the scheme.

4.3 Regulation of Household Heating

Although stove heating regulation and the transport component are combined within a single regulatory act, they are two different regimes requiring different instruments. 

The ban on the use of solid fuels is being piloted in nine central districts, covering approximately 2,800 households, while a full citywide ban is planned for 2029. However, the main policy instrument is not the ban itself but the subsidized replacement of heating equipment. According to the data provided, European programmes have funded the free replacement of approximately 20,000 heating devices in around 11,000 households. The current phase of the programme is expected to increase coverage to approximately 22,000 households by the end of 2029. Residents choose the equipment and their decisions are driven mainly by operating costs: 80–90% selected inverter air conditioners, approximately 1,500 households chose pellet boilers;

The heating equipment replacement programme is financed primarily through European and national funds. The total cost of the project implemented under the 2014–2020 Operational Programme Environment (Околна среда) was €22.7 million (BGN 44.3 million), of which €19.3 million was provided by the European Union through the Cohesion Fund and €3.4 million came from national co-financing. A new project provides for approximately €37.6 million (BGN 73.6 million) in grant funding to replace heating equipment in 10,815 homes by the end of 2029. The combined amount of confirmed funding for the two projects is approximately €60.3 million. The budget of the new project corresponds to an average of approximately €3,500 per planned dwelling, or around KZT 2 million.

Figure 2. Map of districts in Sofia where the burning of coal and firewood is prohibited.

The heating equipment replacement program was financed through several successive grants from EU funds, with national co-financing. Overall, funding for stove replacement between 2014 and 2029 amounted to €68.5 million, or approximately KZT 37 billion, across three separate programs. For residents, equipment replacement is completely free of charge. In addition, part of the municipality’s expenditure on zone infrastructure, including cameras and the software for the small and large rings, is also expected to be reimbursed through EU projects and the national budget. Across all projects, the average budget is approximately €3,100 per dwelling, or around KZT 1.7 million, for transitioning a household to cleaner heating.

Even partial modernization of household heating at the scale of a single city required grants amounting to tens of millions of euros. For Almaty, this is a significant conclusion: Sofia’s model relies on access to EU Structural Funds and the Cohesion Fund, which are not available to Almaty. Comparable replacement program, based on Sofia’s target coverage of approximately 20,000 households, would therefore need to be financed primarily from the city or national budget, or through international donor funding. Estimating the total cost of the reform, including the cost of one equipment replacement multiplied by the target number of households, plus capital and operating expenditure for cameras and billing infrastructure, is therefore a necessary next step in the reform’s budget planning.

A key element of social protection is the rule under which households that have applied for equipment replacement and are awaiting installation are not subject to fines. This measure encourages households to join the stove replacement program at an earlier stage.

Enforcement of the ban is inherently limited: fuel is burned inside private homes, which inspectors cannot enter without a legal basis. The city administration is testing the use of drones equipped with sensors and thermal imaging cameras and also responds to complaints from neighbors. Nevertheless, according to the information provided, only around 300 fines have been issued across the entire city since the beginning of the year. This figure confirms that, in the household heating sector, fines are a secondary rather than primary policy instrument.

The differences between the two regulatory regimes are summarized in the table below.

Parameter	Transport Component	Heating Component
Regulated activity	Public activity: entering the zone via a public road	Private activity within a residential property
Detection method	Automated and scalable (cameras and registry)	Manual and targeted; no right of access to private homes
Identification of the violator	Unambiguous, based on the vehicle registration number	Requires proof that fuel was burned
Main instrument	Restriction and fine	Subsidized equipment replacement; fines play a secondary role
Main social risk	Regressive burden on owners of older vehicles	Risk of increased poverty if operating costs rise
Key constraint	Legal framework for enforcement	Public trust and the operating cost of alternatives

5. Public Perception and Communication

Communication with the public was raised by every participant in the meetings, regardless of institutional affiliation, which in itself indicates its systemic importance. The views expressed can be broadly divided into unsuccessful practices and effective practices.

Unsuccessful practices. During the first two years of the zone’s operation, residents did not have a clear understanding of the basic parameters of the regime, including the categories of vehicles subject to restrictions, the boundaries of the zone, and the period during which the restrictions applied. An information campaign was funded; however, as noted during the meeting with municipal council members, it was placed on public transport and therefore targeted an audience that was already not using private cars. The principal target group, owners of older vehicles, predominantly residents of outlying districts, remained largely unreached. The effectiveness of the campaign was not measured, and no dedicated budget was provided for targeted communications. Direct outreach at the local level was identified as the only effective channel for peripheral communities.

Effective practices. Three replicable mechanisms were highlighted during the meetings.

The first was the sequencing of measures. The restrictions were preceded by an expansion of the metro network and the introduction of a new ticketing system, making it possible to present the restrictions as a continuation of improvements that had already been delivered. The Transport Department formulated this as a general principle: restrictions are best introduced on the back of a successful improvement in transport alternatives.

The second was a warning period. A first violation resulted in a warning rather than a fine. As noted during the meetings, it was notifications rather than sanctions that contributed most significantly to the reduction in violations.

The third was the use of everyday communication channels and trusted sources. The city administration’s rapid-information channel in a messaging app, with approximately 43,000 subscribers, proved more effective than the official website. On health-related matters, medical professionals were identified as the most trusted source of information. At the meeting with the medical association, participants presented an earlier study based on data from two city hospitals and the ambulance service. According to the study, days with peak pollutant concentrations were associated with an increase in exacerbations of respiratory diseases and cases of myocardial infarction. These findings were used to develop a communications message comparing mortality attributable to air pollution with fatalities from road traffic accidents. In addition, a training course in environmental medicine was introduced, and work with children in disadvantaged neighbourhoods was organized as a way of reaching and influencing parents.

The positioning of the medical association deserves particular attention. Its deliberate distance from activist rhetoric and emphasis on its expert status gave it access to programmes run by the city administration and the national health authority that were not accessible to protest-oriented organizations.

Systemic gap is the absence of public perception measurement. The zone is assessed using indicators such as the number of violations and pollutant concentrations, while public attitudes are not measured. The methodology of public perception indices used by Almaty Air Initiative in Almaty, which separately assesses awareness, emotional attitudes and readiness to act, is not currently used in Sofia. During the meeting with the expert organization, this approach generated interest in possible cooperation.

6. Monitoring and Impact Assessment

A critical point raised during the meeting with the medical association and confirmed by the other participants was that it is impossible to assess what is not measured. There are no monitoring stations within the boundaries of the low emission zone. According to the information provided, the entire city is served by five official PM10 monitoring stations and one PM2.5 station. These stations belong not to the city but to a national authority which, in the general view of participants, provides only the minimum level of monitoring necessary to comply with regulatory requirements. At the same time, approximately 300 citizen-operated monitoring sensors are in use, meaning that monitoring of the reform relies to a significant extent on non-governmental initiatives.

The consequences of this limitation have become directly apparent. The reported reduction in nitrogen dioxide concentrations, approximately 10–13% in the first half of 2026 compared with 2025, and the 88% reduction in the number of days exceeding the PM10 standard, were calculated using indirect data. Given that the 2025/26 heating season was anomalous in terms of the frequency of temperature inversions, the city lacked a tool capable of separating the effect of the zone from meteorological influences. The mathematical modelling required to isolate the impact of the zone was commissioned only three years after its launch. As a result, in debates at the municipal council level, opponents cite estimates suggesting that the zone makes only a minimal contribution to reducing emissions, while the administration has only its own model-based estimate available.

Monitoring of the primary and related impact indicators of a low emission zone should be an integral part of the zone’s design. In order to evaluate the success of the reform and to defend it against criticism, monitoring stations should be installed inside the zone and along its boundaries, baseline measurements should be conducted before launch, and modelling should be undertaken to distinguish the effect of the policy from other factors. Equipment choices are made by residents based on operating costs, which means that climatic conditions must be taken into account. In particular, Sofia’s model, which relies heavily on inverter air conditioners, is not directly applicable to Almaty’s harsher climate.

Key Indicators (Summary Table)

Summary of the key indicators presented in the report, for citation and presentation purposes.

7. Lessons from Sofia and Implications for Almaty

Analysis of Sofia’s experience makes it possible to identify seven key lessons. Each of these was confirmed by several independent sources during the visit and is presented together with a practical implication for the reform in Almaty.

1. Start by diagnosing the main sources of harm to health. Prioritization should be based not on how easy a source is to regulate administratively, but on its contribution to concentrations of the most hazardous particulate fraction, PM2.5. In Sofia, as in Almaty, although Almaty also has CHP-2 and CHP-3, one of the priority sources is solid-fuel heating in the private residential sector. The city therefore had sound grounds for beginning the reform with an inventory of private households. At the same time, fines proved to have very limited applicability in the heating sector, (only around 300 administrative acts issued citywide over six months) whereas the real driver of progress was the use of incentives, namely subsidized replacement of heating equipment. 

For Almaty: conduct its own inventory of the private residential sector before introducing restrictions; design the heating component around a combination of “incentive + sanction,” with subsidized equipment replacement, rather than fines, carrying the main policy burden.

2. Inter-agency coordination, shared databases and political will. Sustainable impact can only be achieved through coordinated action by the environmental, transport, energy and healthcare sectors around a common objective, supported by compatible databases that are mutually accessible. Sofia’s experience offers several lessons in this regard: fragmented data and reliance on external contractors limit the city’s ability to make and substantiate decisions. One effective instrument was a single cross-sectoral plan, comprising approximately 65 measures across five sectors. Political will driving the process is equally important. Notable examples include the personal involvement of the city leadership, particularly the Mayor, and Sofia’s participation in international initiatives such as Breathe Cities, which provide an external framework of commitments. 

For Almaty: establish a single inter-agency plan with a common objective and a designated coordinating body; develop shared databases instead of maintaining fragmented departmental systems; and ensure political leadership at the highest level of the city administration.

3. Building constituencies in support of the reform. Unpopular measures can only be implemented successfully if there is a coalition of supporters. In Sofia, this support came from doctors and independent medical associations that framed the issue in terms of health, as well as from some residents and civil society organizations. The medical community proved to be the most trusted communications channel, with trust in doctors consistently higher than trust in politicians.

For Almaty: deliberately build alliances with doctors, health associations, expert NGOs and residents through expert-based positioning; use the medical community as a key channel for communicating with the public.

4. Support measures must be an integral part of the reform. The purpose of the reform is to reduce pollution and protect health, not to generate revenue; financial returns should not become a motive for the reform. Restrictions must be accompanied by targeted support in order to avoid exacerbating inequality and poverty. Owners of the oldest vehicles and households relying on solid fuels are generally among the least affluent groups. 

For Almaty: identify funding sources in advance; fully subsidize equipment replacement for vulnerable households; map such households at the address level; protect households awaiting replacement from sanctions; and avoid treating charges and fines as a source of revenue.

5. Provide transport alternatives before introducing large-scale restrictions. Restrictions should be introduced only after the city has created genuine opportunities for a modal shift, including improved public transport, park-and-ride facilities at the boundaries of the zone, and alternative bypass routes. The sequence adopted in Sofia, where the zone was introduced after the expansion of the metro and the launch of a new ticketing system, made it possible to present the restriction as a continuation of improvements that residents had already received.

For Almaty: strengthen and clearly communicate efforts to expand public transport, provide free park-and-ride facilities and bypass routes, and only then introduce restrictions, positioning them as the second part of an improvement already delivered.

6. Certainty of enforcement, equality before the law and prevention of circumvention. When introducing charges or fines, the priority should be a complete and closed enforcement chain, rather than the size of the sanction itself. The rule should apply to everyone regardless of status, and circumvention should be technically impossible. One weak point in Sofia was residual corruption at vehicle inspection stations, which allowed high-emission vehicles to receive a positive environmental assessment. The ability to “buy” a successful inspection undermines the entire system of linking restrictions to a vehicle’s environmental category. 

For Almaty: before launch, establish a complete process from detection to issuance of a payment notice for vehicle movement, using the existing Almaty Parking billing infrastructure; consider an entry-charge model instead of outright vehicle restrictions, as also recommended by Sofia’s expert community; and ensure the integrity of vehicle inspection procedures as a core element of the reform.

7. Exemptions should be based solely on social equity. A system of exemptions is to some extent inevitable, but exemptions should be based on the principles of social equity, rather than on status or place of registration. In Sofia, the exemption granted to residents of the zone holding parking permits led to manipulation of residential registration and diluted the effectiveness of the restrictions. 

For Almaty: target exemptions at vulnerable groups and design them so that they cannot be used as loopholes; ideally, provide vulnerable social groups with a free transitional period with a clearly defined end date.