Delhi and its adjoining areas have been covered under a blanket of thick smog since last morning and the air quality has plummeted to the 'Severe' category and the air quality index reported over 400 in several areas.

The Commission for Air Quality Management (CAQM) had called the early-morning dense smog an "episodic event" and said they expect the situation to improve by today but the dangerous levels of AQI have forced the CAQM to implement stage III of the Graded Action Response Plan. The measures will be implemented from 8 am tomorrow.

What is GRAP III

• It is the third phase of anti-pollution measures that are implemented when AQI reaches 'Severe' (401 to 450).
• Construction and Demolition Activities: A strict ban on non-essential construction and demolition work, with exceptions for projects critical to national security, healthcare, and certain public infrastructure projects.
• Vehicle Restrictions: Ban on the operation of BS-III petrol and BS-IV diesel four-wheelers in Delhi and parts of the NCR like Gurugram, Faridabad, Ghaziabad, and Noida.
• Restrictions on the use of diesel generator sets for emergency purposes only. Industrial operations not running on fuels in the standard list of approved ones are banned.
• Intensifying mechanized road sweeping and water sprinkling to suppress dust. Increasing public transport services and promoting off-peak travel through differential rates.
• Major welding and gas-cutting operations. Minor welding activities for MEP (Mechanical, Electrical and Plumbing) works are to be, however, permitted.
• Painting, polishing and varnishing works etc. Cement, Plaster / other coatings, except for minor indoor repairs/ maintenance. Cutting/grinding and fixing of tiles, stones and other flooring materials, except for minor indoor repairs/ maintenance. Waterproofing work (Excluding Chemical waterproofing).
• Movement of vehicles carrying construction materials on unpaved roads.

GRAP, implemented in the region during the winter season, actions in 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). 

GRAP II was enforced in Delhi in October after the air quality was recorded at over 300.

GRAP Stage 1 (AQI 201-300)

• Periodic mechanised sweeping and water sprinkling on roads.
• Dust mitigation at construction sites. Proper waste management.
• Strict checks on polluting vehicles, better traffic management, and emission controls in industries, power plants, and brick kilns.
• Bans on open burning of waste, limited use of diesel generators, and no use of coal or firewood in eateries. 
• Quick actions for redressal of complaints on 311 APP, Green Delhi App, SAMEER App and other such social media platforms to curb polluting activities. 
• Encourage offices to start unified commutes for employees to reduce traffic on the road.
• Advisory to celebrate festivals in an eco-friendly manner by avoiding firecrackers.

GRAP Stage 2 (AQI 301-400)

• Mechanised sweeping and water sprinkling on roads daily. Focussed and targeted action for abatement of air pollution in all identified hotspots
• Uninterrupted power supply to discourage the use of alternate power generating sets.
• Enhance vehicle parking fees to discourage private transport.
• Resident Welfare Associations are required to provide electric heaters to security staff.
• Augment CNG/electric bus and metro services by inducting additional fleet and increasing the frequency of service. 

GRAP Stage 4 (AQI >450)

• Stop entry of truck traffic into Delhi. Ban on construction and demolition activities for linear public projects such as highways, roads, flyovers, overbridges, power transmission, pipelines, telecommunication etc.
• The government can discontinue physical classes, including Classes Vl - lX and Class Xl.
• The government is to decide on allowing public, municipal and private offices to work on 50% strength and the rest to work from home.
• State governments may consider additional emergency measures like the closure of colleges/educational institutions and closure of non-emergency commercial activities, permitting the running of vehicles on the odd-even basis of registration numbers etc.
• Children, the elderly and those with respiratory, cardiovascular, cerebrovascular, or other chronic diseases to avoid outdoor activities and stay indoors.