Volunteers have handed out green pollution masks to residents of India's capital to make a statement about the city's choking smog.
Authorities have closed schools and stopped most lorries from entering New Delhi this week as they try to mitigate what officials are calling a public health emergency.
New Delhi is one of the world's most polluted cities. The worst air quality often hits this time of year as nearby farmers burn fields, people build street fires to keep warm and winds die down.
Arun Bansal, who was helping coordinate Thursday's effort, said the masks are not a solution but help raise awareness of the problem.
He said he hopes they might make the average person in the developing nation think twice about what they are doing.
"Maybe he will not burn papers or he will discourage others who are burning all those things," Mr Bansal said.
The inexpensive masks probably have only a limited impact on keeping out microscopic particles that can affect breathing and health.
Other people in the city have purchased their own masks or have taken to wearing scarves over their mouths. Some are choosing to stay away from work or limiting the time they spend outdoors.