New Delhi: For Maharashtra and Gujarat, the winter of 2022-23 had been the most polluted in the last four years – says a new analysis by the Centre for Science and Environment of the region’s winter air quality trends.

The analysis was done for the period October 1, 2022, to February 28, 2023. In these states, winter pollution typically sets in during late November and early December, when the cooler and calmer conditions trap local pollution.

“The fact that the big cities, as well as smaller towns, have experienced the rise in winter PM2.5 levels points to the rapid spread of the air pollution problem in this region. This is evident in both the seasonal average and the peaks. While local pollution is increasing in these rapidly motorizing and developing cities, the regional influence is further aggravating the challenge. This is overpowering the advantage of natural ventilation of the coastal climate. This demands an immediate roadmap to control pollution from the key sources across the region,” says Anumita Roychowdhury, executive director of research and advocacy, at CSE.

“While in absolute terms Gujarat has a higher pollution level, it is rising faster in Maharashtra. The most polluted locations in the region are located in Mumbai and Navi Mumbai. Vapi and Surat are among the most polluted locations in Gujarat. Nagpur registered the highest increase in pollution with a 105 percent rise compared to the previous winter,” says Avikal Somvanshi, senior programme manager, Urban Lab, CSE.

This analysis is part of the third edition of Urban Lab’s Air Quality Tracker Initiative which was started in the winter of 2020-21. This analysis is based on the real-time data available from the current working air quality monitoring stations in these two states. A huge volume of data points have been cleaned and data gaps have been addressed, based on USEPA methods, for this analysis. Winter here is defined as the period between October 1, 2022, and February 28, 2023. The winter average is based on the mean of daily averages where continuous data is available since 2019.