Scientists at the System of Air Quality Forecasting and Research (SAFAR), a joint project of Indian Institute of Tropical Meteorology and Indian Meteorological Department, said the change can be linked to the amount of crackers burst at these locations. "Our model analysis shows meteorology did not play any decisive role in this surprising switch in pollution levels at these locations. I think it is because fewer crackers were burst at Pusa and vice versa," said Gufran Beig, chief project scientist, SAFAR.

For the past three years, Lodhi Road has emerged as the least polluted area, along with Aya Nagar, during Diwali and the next day. However, this year, Lodhi Road had the worst air quality, which indicates a drastic increase in local emissions," he added. An analysis of the amount of crackers burned by Pusa residents should confirm whether the results could be fully explained by this.

Delhiites continued to breathe very polluted air even on Saturday, two days after Diwali. This smog-like condition may clear away in a couple of days, only to come back again as the temperature is likely to fall in the next week. Beig explained that the air has a lot of moisture which is holding the pollutants.

IMD had predicted light rain on Saturday but that didn't happen. This led to further accumulation of particulate matter. Lodhi Road, Noida and DU recorded the highest PM2.5 (fine, respirable particulate matter) and PM10 (coarse particles) on Saturday.

Peak pollution levels, according to real-time data released by Delhi Pollution Control Committee, were very high on Saturday. Around 2.15pm at Civil Lines, PM2.5 value was 332.83 microgram per cubic metre, about five times the standard, and PM10 level was 597.55 microgram per cubic metre, six times the standard. At Anand Vihar, PM2.5 level was 594 microgram per cubic metre, about 10 times the limit, and PM10 level was 1,024 microgram per cubic metre, also 10 times the standard, at 1.10pm.