Every winter, as inversion leads to smog-filled days and nights across entire north India, the western region of the country — by contrast — looks much cleaner. A new analysis of regional air pollution levels, done by Centre for Science and Environment (CSE), says air pollution is rapidly becoming a matter of concern in the western states of Maharashtra and Gujarat as well.
Winter pollution sets in these states during late December and early January when cooler and calmer conditions trap the local pollution, which is high. Even though winter pollution levels in the western region are not as high (as that seen in the Indo-Gangetic Plains) due to its proximity to the sea and improved ventilation, the levels have been seen to be increasing despite the geographical advantages and favorable meteorology, says the analysis.
“This analysis of real time air quality data for the period 2019-2021 shows that the downward dip in pollution that was induced by the lockdown phases of the pandemic in 2020, is changing. Pollution levels are threatening to bounce back – they are already rising in 2021. In many cases, the levels are even higher than in 2019″ says Anumita Roychowdhury, executive director, research and advocacy, CSE.
“The number of bad-air days in Mumbai have doubled between 2019 and 2021, while good days are down by 20 per cent. This underscores the urgency of scaling up action across all sectors to prevent further worsening and to arrest the trend in this region,” she added.
“Even though real time air quality monitoring has begun to expand in these states to provide more up-to-date information on air quality, there are serious concerns around missing data and gaps that makes proper risk assessment difficult. In some stations of Maharashtra and Gujarat, data availability is so low that the trend cannot be assessed. Quality control of data is necessary,” says Avikal Somvanshi, programme manager, Urban Data Analytics Lab, CSE.
This new analysis of real time pollution data is part of CSE’s air quality tracker initiative. The objective of this new analysis is to understand the trends and magnitude of pollution in different regions that have real time air quality monitoring systems. This is an assessment of annual and seasonal trends in PM2.5 concentration for the period January 1, 2019 to January 9, 2022.
This analysis is based on the real time data available from the current working air quality monitoring stations. For the analysis, a huge volume of data points have been cleaned and data gaps addressed based on the USEPA (United States Environmental Protection Agency) methodology.
The analysis covers 56 continuous ambient air quality monitoring stations (CAAQMS) spread across 15 cities in two states: Maharashtra — one station each in Aurangabad, Kalyan, Nagpur, Nashik and Solapur, two in Chandrapur, four in Navi Mumbai, eight in Pune, and 21 stations in Mumbai; and Gujarat — one station each in Ankleshwar, Nandesari, Vapi and Vatva, four in Gandhinagar, and eight stations in Ahmedabad.
Somvanshi points out that even though there are multiple real time monitors in a few cities of these states, many of them could not be considered for long-term analysis due to data gaps and lack of quality data.
Moreover, in several cases, the real time monitors have been set up recently and therefore, long-term data is not available. Several cities of Gujarat have got their real time monitors in June 2021. Many stations in Maharashtra have got their real time monitors in June 2019 and November 2020. Thane station stopped reporting PM2.5 data in early 2019, therefore it could not be included in this analysis.
Says Roychowdhury: “The western region has its own unique challenges and will have to be addressed. Pollution trapping can be high during adverse winter conditions, as the overall pollution levels in cities are high.”
The region is already experiencing a rebound of pollution after the temporary dip in 2020 due to the pandemic-linked hard lockdown phases. Key industrial towns and clusters are located in these two states that require attention. Maharashtra is among the states with the highest number of non-attainment cities under the National Clean Air Programme, she added.
The CSE analysis recommends stronger multi-sector interventions to reduce pollution in a time-bound manner, meet the national ambient air quality standards, and prevent further worsening of the trend.
This requires massive scaling up of the access to clean fuel and technology in industry and power plants, transformation of public transport, walking and cycling at a scale, renewal of vehicle fleet, rapid electrification of new vehicle fleet, amendment of municipal bylaws based on central waste management rules and regulations and scaling up of infrastructure for management and recycling of all waste streams, elimination of solid fuels for cooking, controlling dust from construction sector and adopting greening and afforestation strategy for dust control. “This agenda is non-negotiable to meet the clean air target, says Roychowdhury.
