Volunteers have taken to the streets of India's capital and fitted green pollution masks over the mouths of willing residents to make a statement about the city's choking smog.
Not everybody wanted to play along and some batted the masks away.
Authorities have closed schools and stopped most trucks 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..