Delhi Deputy Chief Minister Manish Sisodia called a high-level meeting on Tuesday to discuss steps to combat pollution on a ‘war footing’. Ministers and officials of all concerned departments were present at the meeting that took place at the Delhi Secretariat, reported PTI. However, details from their discussions have not been released yet.

The meeting comes after Delhi woke up to extremely dangerous levels of pollution following Diwali celebrations on the weekend. Dipping mercury levels and lack of winds caused a harmful mix of respirable pollutants and toxic gases to remain close to the surface, thus worsening the air quality.

The situation improved marginally on Tuesday but the NCR's air quality remains in the "hazardous" category. The Central Pollution Control Board said that PM 2.5 levels (particulate matters that are 2.5 or less than 2.5 micrometres in diametre) in Delhi came down to 391. Places like Anand Vihar and RK Puram – the two most polluted areas of Delhi – had readings of PM 2.5 at 672 and 599, respectively. PM 10 levels (particulate matters that are 10 or less than 10 micrometres in diametre) in the city came down to 836.1 micrograms per cubic metres.

On Monday, concentration of PM 2.5 had risen from 643 to beyond 999 micrograms in various areas, which is several times higher than the safe limit of 60 micrograms per cubic metres. PM 10 had also been more than 999 micrograms per cubic metres, much higher than the safe limit of 100 micrograms. Cities like Mumbai, Pune, Lucknow, Kolkata and Ahmedabad also woke up to higher levels of air pollution on Monday.

In Mumbai on Tuesday, levels of PM 2.5 dropped to 155 from 494, while in Pune, it came down slightly to 329 from 400. Lucknow also witnessed a significant drop from 834 to 283 while the air in Kolkata improved from "very unhealthy" level to "unhealthy levels". In Ahmedabad, too, it dropped to 186.

Air quality levels in charts:

Credit: Air Quality Index
Credit: Air Quality Index
Credit: Air Quality Index
Credit: Air Quality Index
Credit: Air Quality Index
Credit: Air Quality Index