Delhi recorded its air quality in the "very poor" category on Friday and strong surface winds are likely to bring some relief from high pollution levels Sunday onwards, authorities said. The city recorded its 24-hour average air quality index at 347, down from at 375 on Wednesday.
Neighbouring Faridabad (349), Ghaziabad (360), Greater Noida (308), Gurugram (323) and Noida (336) also recorded their air quality in the 'very poor' category.
"The air quality is likely improve significantly from November 21 owing to relatively strong winds and reach poor category. PM2.5 to be the predominant pollutant," the central government's Air Quality Early Warning System for Delhi said.
According to the Ministry of Earth Sciences air quality monitor SAFAR, 773 farm fires in neighbouring regions accounted for two per cent of Delhi's PM2.5 pollution on Thursday.
The stubble burning contribution is "negligible" because the transport-level winds are coming from the east direction preventing intrusion of pollutants.
Earlier in the day, Delhi Environment Minister Gopal Rai urged his Union counterpart Bhupender Yadav to call a joint meeting and prepare an action plan to tackle air pollution in Delhi-NCR.
Rai also cited a study from Indian Institute of Tropical Management (IITM), a central government-run body, that external sources accounted for 69 per cent share in Delhi's air pollution between October 24 and November 8.
He said that a similar study by TERI in 2016 had shown that 64 per cent pollution is due to external sources and 36 per cent pollution is due internal source of Delhi.
To combat pollution, the Delhi government on Wednesday issued 10 directions, including a ban on the entry of trucks carrying non-essential items in the city and closure of schools and colleges till further orders.
The Delhi government has banned construction and demolition activities in the city till November 21. It has also ordered its employees to work from home till Sunday.
The city government had earlier announced the closure of all schools, colleges and educational institutions till Sunday and banned construction and demolition activities till November 17. Rai said 1,000 private CNG buses will be hired to strengthen the public transport system.