Context: A government panel tasked with improving the air quality in Delhi and its adjoining areas has made crucial changes to a set of anti-air pollution measures followed in the region in winter.

Key-highlights of the changes

• The changes include strict restrictions on the plying of overage vehicles and a complete ban on the use of coal and firewood in eateries, restaurants and hotels when the air quality index (AQI) breaches the 200 mark.

• In addition, BS III petrol and BS IV diesel four-wheelers will be immediately if the AQI crosses the 400 mark.

Bharat Stage (BS) Emission Standards (BSES)

• The Bharat Stage (BS) Emission Standards (BSES) were introduced by the Government of India in 2000, and are set by the Central Pollution Control Board (CPCB) under the Ministry of Environment.

• ‘BS’ stands for Bharat Stage, the emission regulation or fuel standards mandated by the government of India for motor vehicles.

• BS-I was launched in 2000

• BS-II in 2001 (nationwide in 2005)

• BS-III in 2005 (nationwide 2010)

• BS-IV in 2010 (nationwide 2017)

• There is no BS-V, and BS-VI arrived in 2017 (nationwide 2020).

• BS-VI or less polluting emission norms were mandated across the country from April 1, 2020, which meant that all new vehicles being manufactured after the norms were forced to comply with the new standards that cover four-wheelers, two-wheelers as well as commercial vehicles.

Amended GRAP

• The Commission for Air Quality Management (CAQM), a statutory body formed under an Act in 2021, had amended the Graded Response Action Plan (GRAP), first notified in 2017, in July last year also to ensure proactive implementation of anti-air pollution steps based on forecasts -- up to three days in advance.

GRAP is classified under four different stages of adverse air quality in Delhi

• Stage I – ‘Poor’ (AQI 201-300)

• Stage II – ‘Very Poor’ (AQI 301-400)

• Stage III – ‘Severe’ (AQI 401-450)

• Stage IV – ‘Severe Plus’ (AQI greater than 450)

The revised GRAP now recommends strict enforcement of the orders of the Supreme Court and the National Green Tribunal on overage diesel and petrol vehicles under Stage 1.

• It also calls for a complete ban on the use of coal and firewood in eateries, restaurants and hotels if the AQI crosses the 200 mark

• The new steps suggested in the revised GRAP include “strict action to curb air pollution at all identified hotspots in the region under Stage 2”.

• Under Stage 3, states must impose strict restrictions on the plying of BS III petrol and BS IV diesel four-wheelers.