Rain in Delhi may keep Grap steps at bay till Oct 8

According to the India Meteorological Department (IMD), light rain is expected over the Capital from October 4 to October 8, due to a low-pressure area currently over the Bay of Bengal, which will gradually move towards northwest India.

While measures under the new Graded Response Action Plan (Grap) can be enforced any time after October 1—as soon as the Air Quality Index (AQI) falls into the “poor” category with a reading of 201 or higher—authorities will likely hold off until at least October 8, with rain expected to come to Delhi’s rescue, forecasts show.

There is possibility of very light rain on October 4, and light rain and thunderstorm activity on October 5. The air quality is likely to remain largely in the ‘moderate’ to ‘satisfactory’ category after that, IMD forecast said. (PTI)

Delhi’s AQI was recorded at 181 (moderate) on Sunday according to Central Pollution Control Board’s daily 4pm national bulletin. This is slightly less than Saturday’s reading of 186 (moderate) and forecasts by the Early Warning System (EWS)—utilised by the Commission for Air Quality Management (CAQM) sub-committee on Grap—show AQI will remain in the “moderate” category on Monday as well. It is expected to start improving gradually as light rain hits Delhi on Tuesday.

An AQI reading between zero and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.

Delhi recorded a maximum temperature of 34.7 degrees Celsius on Sunday, which is around normal for this time of the year, and a minimum temperature of 23.7 degrees Celsius—one degree above normal. IMD’s forecast for Monday shows clear skies, with the maximum and minimum expected to hover around 35 and 23 degrees Celsius.

According to the India Meteorological Department (IMD), light rain is expected over the Capital from October 4 to October 8, due to a low-pressure area currently over the Bay of Bengal, which will gradually move towards northwest India. “This will bring moisture-laden easterly and southeasterly winds to the region, and, as the weather system moves closer to northwest India and Madhya Pradesh, the intensity of rain will increase,” a met official said, adding that while only drizzle activity is expected on Tuesday, light showers will commence from October 5 until October 7, with the intensity of rain expected to be highest on October 6 and 7.

“On those two days, moderate rainfall is expected the region, and snowfall is expected in the mountains. From October 8 onwards, rain intensity will reduce again and from October 9, dry northwesterly winds may return,” the official said.

According to the EWS forecast, Delhi’s AQI is likely to remain in the upper end of the “moderate” category on both Sunday and Monday, with little chances of it touching “poor”.

“Air quality will improve after that but will remain in the ‘moderate’ category from October 4 to October 5. There is possibility of very light rain on October 4, and light rain and thunderstorm activity on October 5. The air quality is likely to remain largely in the ‘moderate’ to ‘satisfactory’ category after that,” the forecast said.

VK Soni, a scientist at IMD and part of the CAQM sub-committee on Grap, said with AQI not expected to touch “poor” yet, no measures need be enforced. “If we expect poor air, then a meeting can be held and accordingly, action can begin on the ground. At present, rain will regulate the air quality,” he said.

Under stage 1 or the “poor” category, the measures that can be invoked include agencies carrying out mechanised sweeping and sprinkling of water on roads; halting work at all construction and demolition projects with an area of over 500sqm that have not registered themselves on the state government’s web portal (which monitors C&D sites) and visibly polluting vehicles being either impounded or fined. Under the category, diesel generator sets cannot be used as a regular source of power supply, but only as a back-up.