The 54-year-old twins have kept up their daily run

despite New Delhi's Air Quality Index recently hovering close to 500

Over the past seven years, they have completed dozens of marathons and ultra marathons

and they typically run for anything between 90 minutes and four hours each day

(Ram Babu Gupta, Marathon runner)

"We are facing problems due to pollution. Firstly, we breath heavily, we feel irritation in our throats. There's coughing and so we wear this mask. Also, there is a slight irritation in the eyes."

(Shyam Babu Gupta, Marathon runner)

"We are taking precautions which include, drinking lukewarm water, eating cane sugar, and continuously washing our eyes with cold water. We also want to give this message to everyone, especially to the elderly and the children, do not step out of the house unless it is necessary."

City authorities have shut all schools, stopped construction activities

and say they will impose restrictions on vehicle use to control pollution