The Shri Ram School Aravali, Shri Ram School Moulsari (except class 10 and 12), Heritage School and Shiv Nadar School (pre and primary wing) announced a holiday on Friday as Delhi deals with the worst smog it has seen in17 years. The thick blanket of pollution mixed with fog also caused low visibility and breathing problems for a second day.

“The Heritage school has decided to shut down tomorrow in response to the disturbing levels of pollution in the city. Unless and until we collectively take action, the city is going to sink deeper into this crisis. The city administration definitely needs to wake up, acknowledge and resolve this issue that is taking a toll on our health and the health of our kids. I would urge the other schools also to follow suit,” said Kaye Jacob, principal of The Heritage School, on Thursday

Among other measures, the Shiv Nadar School introduced jaggery in its menu for students, known for its body cleansing properties, a school official said.

Other schools, including Scottish High International School, Lancers International School, Ridge Valley School, Ryan International School, Vega school and Presidium School, have asked parents to give their children masks. Schools have also cancelled outdoor activities for the coming days.

A note by Scottish High Internationals School stated, “Children may use masks to protect from pollutants present in the air. Air filtering Masks such as Vog masks available in the market and N95 masks can be procured from local pharmacies and online. All children with known history of asthama and bronchitius are advised to carry their inhalers/ any other medication advised by the doctor with them.”

Vega School, which is equipped with air quality readers, will not allow students outdoors on days the air pollution index (API) is high. Sandy Hooda, co-founder of the school, said the administration will be introducing red flag days -- days on which the API levels are more than 300. Students will be kept indoors on these days.