With air pollution levels in Delhi coming down to the 'poor' category from 'very poor', the Commission for Air Quality Management has said it will review the situation on Friday.

The Centre's air quality panel may take a call on revoking curbs in place in Delhi-NCR under stage 3 (severe) of the Graded Response Action Plan (GRAP), an official said on condition of anonymity.

The panel also issued an order on Thursday, asking authorities to immediately stop polishing, varnishing and painting work at construction sites as these activities create volatile organic compounds which further increase the toxicity of the air and cause harm to human health.

"These activities cannot be treated as non-polluting category of construction and demolition activities under the clause 4 (iii) of Stage-III of GRAP and need to be stopped at projects sites, whenever GRAP Stage-III orders are invoked or in operation," the order read.

All construction and demolition work, except for essential projects, is banned in Delhi-NCR under stage 3 of GRAP.

Brick kilns, hot mix plants and stone crushers are also not allowed to operate.

"The CAQM is keeping a close watch on the changing air quality scenario of Delhi-NCR and accordingly, its Sub-Committee on Graded Response Action Plan will convene a meeting tomorrow to comprehensively review the situation for appropriate decision," the air quality panel said in a statement.

The air quality in Delhi improved on Wednesday owing to favourable wind speed at night, sporadic rains in adjoining states and a considerable drop in emissions from stubble burning.

The 24-hour average Air Quality Index (AQI) in the national capital stood at 295 on Thursday. It was 260 on Wednesday, 372 on Tuesday, 354 on Monday, 339 on Sunday and 381 on Saturday.

The AQI recorded on Wednesday was the lowest since October 20, when it was 232. For November, it was the best AQI since November 29, 2020, when it was 231, according to Central Pollution Control Board data.

An AQI between 201 and 300 is considered 'poor', 301 and 400 'very poor', and 401 and 500 'severe'.

V K Soni, head of the India Meteorological Department's Environment Monitoring and Research Centre, said favourable wind speed -- 10 to 18 kmph -- is predicted to bring a considerable improvement in the air quality from November 11.

The Delhi government had on Monday decided to reopen primary classes from November 9 and revoke the order asking 50 per cent of its staff to work from home in view of the improvement in the city's air quality over the last few days.

However, BS-III petrol and BS-IV diesel four-wheelers stayed off Delhi roads under stage 3 of GRAP.

On Sunday, the CAQM had directed authorities to lift the ban on plying of non-BS VI diesel light motor vehicles in the region and the entry of trucks into the capital imposed under stage 4 of the GRAP.