The Delhi government has made the use of anti-smog guns (ASGs) mandatory for all the construction activities in the city with detailed guidelines being issued regarding the same. Currently, the Delhi Metro Rail Corporation (DMRC) has included 14 ASGs to combat air pollution while its phase 4 expansion is taking place. Experts at the DMRC have said that the guns work by throwing fine mist from time to time to check the possibility of dust pollution emanating from the construction work. They also added that the water being used is free from pollutants and that more such ASGs will be introduced gradually in the days ahead.