The air quality in New Delhi continued to remain at hazardous levels on Saturday, while the situation marginally improved in Mumbai, Chennai and Bengaluru.

While the air quality index, or AQI, in New Delhi continued to read 355, the monitor at the United States consulate in Mumbai read 184 at 11 am on Saturday, down from 204 on the day of Diwali. It is still far from the level that represents good air quality.

The primary pollutant measured by the index is PM 2.5, or particulate matter smaller than 2.5 microns.

In Chennai, the quality of air at the monitoring station at the US consulate read 97, meaning that there was still significant health risk to people sensitive to air pollution.

At Bengaluru BTM, the quality of air recorded an unhealthy 161 on the index on Saturday morning. The day after Diwali, many residents decided to leave the city to escape the polluted air, The Hindu had earlier reported.

Though the pollution levels in Delhi after Diwali were lower than in the past three years, doctors at the All India Institute of Medical Sciences told The Indian Express that the drop was not significant and that it could result in a “dramatic difference in the overall health of an individual”.

India tops the list of pollution-related deaths in the world, a study published by Lancet on Thursday said.

Meanwhile, a study by the Central Pollution Control Board, which was published in the science journal Current Science, found that noise levels post-Diwali were higher in over 85% of the noise monitoring stations across seven cities, The New Indian Express reported. The National Ambient Noise Monitoring Network, which runs 70 monitoring stations in seven cities, keeps a tab on noise pollution through the year.