Delhi recorded its air quality in the 'very poor' category on Sunday morning and forecasters said slow wind speed and an increase in stubble burning, especially in Punjab, may push it to the 'severe' zone.
With pollution levels worsening, the Centre's air quality panel on Saturday directed authorities to impose a ban on construction and demolition activities in Delhi-NCR, except in essential projects, and other curbs under stage III of the Graded Response Action Plan.
Delhi's overall air quality index (AQI) stood at 367 at 9 am. The 24-hour average AQI on Saturday was 397, the worst since January. It was 354 on Thursday, 271 on Wednesday, 302 on Tuesday and 312 on Monday (Diwali).
Anand Vihar (AQI 468) was the most polluted place in the capital. Wazirpur (412), Vivek Vihar (423) and Jahangirpuri (407) were among the monitoring stations that recorded "severe" air quality.
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VK Soni, head of the India Meteorological Department's Environment Monitoring and Research Centre, said a layer of smog lingered over the Delhi-NCR on Saturday amid adverse meteorological conditions and it is likely to persist for two more days. Some respite is likely from Tuesday.
SAFAR, a forecasting agency under the Union Ministry of Earth Sciences, said that the share of stubble burning in Delhi's pollution rose to 21 per cent on Saturday, the highest this year so far.
It may increase up to 40 per cent on Sunday and push the air quality into the severe zone, Gufran Beig, the founder project director of SAFAR said.
Delhi Environment Minister Gopal Rai will chair a high-level meeting on Sunday to discuss measures to be implemented under stage III of GRAP.
GRAP is a set of anti-air pollution measures followed in the capital and its vicinity according to the severity of the situation.
It classifies the air quality in the Delhi-NCR under four different stages: Stage I - 'Poor' (AQI 201-300); Stage II - 'Very Poor' (AQI 301-400); Stage III - 'Severe' (AQI 401-450); and Stage IV - 'Severe Plus' (AQI >450).
Under stage III, the authorities have been asked to enforce a strict ban on construction and demolition activities in the NCR, except for essential projects and non-polluting activities such as plumbing, carpentry, interior decoration and electrical works.
The construction ban will not be applicable on projects concerning national security, defence, railways and metro rail among others. However, it is likely to affect housing projects in Noida, Ghaziabad, Gurugram and other areas. Mining activities will not be allowed in the region.
The next stage in the "Severe Plus" category or Stage IV can include steps like a ban on the entry of trucks into Delhi, allowing 50 per cent of staff to work from home in public, municipal and private offices,closure of educational institutions and the plying of vehicles on an odd-even basis, etc.