Smog enveloped Delhi-NCR on Wednesday morning which caused a preemptive disruption to 100 flights and 26 trains which in turn led to slight rainfall during the evening. In conjunction with this, Delhi’s Air Quality Index (AQI) also reached a daunting value of 386 which prompted the Centre to implement GRAP 4 restrictions. As per forecasts by India Meteorological Department and the Indian Institute of Tropical Meteorology, AQI is predicted to surpass the 400 mark in a few days.

According to the IMD, it was projected that clouds would obscure the skies throughout the day, with the possibility of some light rains or drizzles during the day. An IMD report stated that at around 5:30 AM on Wednesday, there was light wind with the Safdarjung area as having 200 meters visibility due to hazy conditions, while Palam was reported to have 150 meters visibility.

As for the predictions, the meteorological department predicted that the cold weather would keep sweeping through Delhi, leading to the issuance of an orange alert for Delhi. “There were reports of fog covering Patna and reducing visibility... We have issued an orange alert in the national capital. A rail or road disruption and bad weather would cause an orange alert to be issued. People have been advised to be cautious while on the roads during dense fog, and use fog lights to improve visibility,” the IMD said.

While the weather remained chilly, with the humidity at 97 percent as per the observations taken at 8:30 AM, it was predicted that the maximum temperature for the day would be around 19 degrees Celsius.

GRAP Stage 4 Re-Implemented in Delhi: Here’s Why it Was Necessary

The CAQM sub committee on 15th January immediately activated GRAP Stage 4. They retracted the restrictions which were placed under stage 3 on the 12th of January when rainfall caused an improvement in the overall air quality index.

As per early reports published by the CPCB, AQI reached 386 today meaning it falls under category ‘very poor’ which is between 301 - 400. CAQM also informed that the AQI has increased from 275 on January 14 to 393 even before 5pm today and then to even 396 by 6pm.

The combination of pollution, low temperatures, and low winds created foggy conditions that were unable to let pollutants disperse. As a result, there was a significant increase in the AQI. The CAQM mandated delhi and NCR authorities to implement all measures under stage 3 and 4 immediately.

All measures under the GRAP schedule will be put into action. There will be regular reviews and monitoring that will take place in all NCR regions and the relevant teams to prevent further dismally high AQI levels. There will be gradual measure revisions and enhanced vigilance. Under GRAP you are expected to comply with the provided citizen charter.

The air quality standards are set under GRAP framework which allows classification air quality into four zones such as Stage 1 (Poor, AQI 201-300), Stage 2 (Very Poor, AQI 301-400), Stage 3 (Severe, AQI 401-450) and Stage 4 (Severe Plus, Above 450).

During the winters the meteorological parameters in the national capital region are not as favourable as required. This, coupled with vehicle emissions, local stubble burning, firecrackers and other pollutants leads to a toxic air quality in Delhi-NCR.