Strengthening the Scientific Foundations of NCAP: Building a Standardised Framework for Source Apportionment and Emission Inventories

Introduction

India’s first comprehensive action plan for air quality management in cities, the National Clean Air Programme (NCAP), was launched by the Ministry of Environment, Forests, and Climate Change (MoEF&CC) in 2019. The programme initially aimed to achieve a 20–30% reduction in PM10 and PM2.5 concentrations by 2024 across 102 identified cities with an emphasis on PM2.5 due to its significant health impacts. In 2022, the Non-Attainment Cities (NACs) list was revised to include 130 cities. In parallel, PM10 was designated as the pollutant of interest, with its reduction as the metric of progress, due to limitations in PM2.5 baseline data. The programme goal was revised to achieve a 40% reduction in PM10 levels, or attainment of national ambient air quality standards
(NAAQS), by 2025–26 in the NACs.

The 130 NACs were chosen based on an analysis of 2017 manual monitoring data from the National Ambient Air Quality Monitoring Programme (NAMP). Among these, more than 40 cities with over a million residents received air quality performance grants through the 15th Finance Commission’s Million-Plus City Challenge Fund. The remaining cities are supported under the ‘Control of Pollution’ budgetary head of the MoEF&CC. Consequently, cities lacking functional monitoring stations or those that did not fulfil the requirement (cities that exceeded NAAQS for five consecutive years from three monitoring stations) were excluded from the NAC classification. This has resulted in the omission of several other polluted cities (such as Ranchi and Howrah) from the NCAP non-attainment list.

The NCAP vision document also outlined a vision for “comprehensive, multi-scale, and cross-sectoral” action to address not only sources within the remit of the MoEF&CC but also those outside it. It also sought to mainstream air pollution action through existing programmes such as the Smart Cities Mission. Additionally, it aimed to convene sector-specific working groups (such as with the Ministry of Power (MoP) to focus on emissions from thermal power plants and the Ministry of Road Transport and Highways (MoRTH) on vehicular emissions) to promote broader action on pollution mitigation. However, there has been little documented progress on the constitution of these working groups, the development of sectoral action plans, or the integration with other programmes.

Based on NCAP goals, the 130 non-attainment cities prepared city action plans detailing source-specific interventions categorised as short-, medium-, and long-term measures, which the CPCB subsequently approved. These city action plans, meant to be backed by analyses that determine source-specific emissions, form the basis for how cities are supposed to approach air quality action under the NCAP. However, five years into the programme, most cities have yet to complete their source apportionment (SA) or emissions inventory (EI) studies, and their role in determining city-level actions remains unclear. In this brief, we highlight the significance of SA and EI studies as the backbone of effective air quality management, and explain why India needs to strengthen its approach to conducting these studies to integrate them into policy actions.