The government on Wednesday issued a health advisory, nearly two days after parts of North India, including the National Capital Region, came under the grip of a dense smog because of poor air quality. Citizens have been advised to stay indoors and avoid morning walks or other strenuous activities.

The Health Ministry also advised people to “drink plenty of water and fluids, not to smoke any tobacco product indoor as well as outdoor and minimise the use of deodorants and room sprays as much as possible”. It asked people to avoid areas with smoke or heavy dust.

Earlier in the day, Environment Minister Harsh Vardhan said his ministry and state governments have identified “every possible step” needed to tackle the situation. In a series of tweets, he said the need of the hour is to put the measures into action at the ground level.

Vardhan said the Centre had responded to the Delhi government’s request to sprinkle water using helicopters, asking it to examine whether it was cost effective when compared to other simpler measures.

“If the government of Delhi thinks that sprinkling of water with helicopters is the most cost-effective measure, it is free to do so,” Vardhan said. “I call for cost-effective measures since management of air pollution requires sustained actions over a long period of time to be effective.”