The combined effect of stubble burning in neighbouring States, local pollutants, and unfavourable meteorological conditions resulted in Delhi’s air quality slipping into the worst — ‘severe plus’ — category for the first time this season on Friday.
The development prompted Lieutenant-Governor V.K. Saxena to call for an emergency meeting with Chief Minister Arvind Kejriwal and Environment Minister Gopal Rai. Mr. Kejriwal, who is leading the Aam Aadmi Party’s poll campaign in Chhattisgarh, did not attend the meeting.
The L-G appealed to people to remain indoors as much as possible, avoid unnecessary travel, and, if necessary, use public transport. A statement from Raj Niwas said Mr. Saxena has appealed to the neighbouring States, especially Punjab, which accounted for 1,921 (71.57%) incidents of stubble burning of a total of 2,684 such incidents on November 1, to curtail crop residue burning.
The city’s air quality index (AQI) score rose from 351 at 10 a.m. on Thursday to 471 at 9 a.m. on Friday and came down to 468 by 4 p.m.
The Graded Response Action Plan (GRAP), a set of emergency measures implemented in Delhi-NCR during the winter, has four sets of responses depending on the severity of air pollution — Stage 1, ‘poor’ (AQI 201-300); Stage 2, ‘very poor’ (AQI 301-400); Stage 3, ‘severe’ (AQI 401-450); Stage 4, ‘severe plus’ (AQI over 450).
The Central government’s Commission for Air Quality Management (CAQM) had on Thursday announced the implementation of Stage 3 of GRAP, which resulted in a ban on construction and demolition activities and plying of BS-III petrol and BS-IV diesel light motor vehicles in Delhi and a few districts in the neighbouring States. All government and private primary schools in Delhi were also closed till Saturday.
However, the CAQM did not press for the enforcement of the final stage of the GRAP, saying the city’s AQI “is already showing a declining trend since afternoon”. As per protocol, Stage 4 should be activated on the basis of forecasts at least three days before the air quality is likely to surpass the 450-AQI figure.
Provisions of the GRAP’s Stage 4 include shutting down educational institutes, reducing staff strength at government and private offices by 50%, and implementing the odd-even scheme for the plying of vehicles, among others.
An official at the weather department said unfavourable weather conditions — low wind speed and lack of rain — are likely to persist for another two to three days.
According to official data for the period between September 15 and October 28, there was a fall of 59% in the number of stubble-burning incidents in Punjab and 40% in Haryana compared to the same period last year. The data also showed a 30.6% rise in the cases of stubble burning in Uttar Pradesh.
However, the Central government’s Commission for Air Quality Management (CAQM) continued with the implementation of Grade III of the Graded Response Action Plan (GRAP), a set of emergency measures taken to reduce air pollution, which kicked in on Thursday evening. Grade IV of GRAP, the final stage of the Centre’s air pollution control plan that should be activated at least three days prior to the AQI surpassing the 450 mark based on forecasts, is yet to come into effect.
Stage IV of GRAP calls for shutting down of education institutes, offices to work at 50% strength, and implementing the odd-even scheme for plying of vehicles, among others. In a statement, the CAQM said the sub-committee noted that Delhi’s average AQI is already showing a declining trend since afternoon. “GRAP Stage-III has been implemented only on Thursday late evening and it’s only reasonable to give time to have its full impact on the average AQI. The actions therein are expected to yield positive results,” the CAQM said.
It added that after comprehensively reviewing the overall air-quality scenario and relevant aspects, it was decided to watch the situation for a day or more, before invoking more stringent disruptive actions under Stage-IV of GRAP.
GRAP categorises actions into four 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 above 450).
