MUMBAI: With the city’s average air quality deteriorating for a week, BMC has issued new air quality guidelines, to be effective from Monday. According to a senior state official, this follows a call from the Prime Minister’s Office to CM Ekanth Shinde asking him to take steps to prevent pollution in Mumbai. The key provisions include dust mitigation measures at all construction sites (including government projects), deployment of anti-smog guns on 60 major roads and expert evaluation of pollution sources like refineries, power plants and fertiliser units. The guidelines are more stringent than ones issued in March. The city has about 6,000 ongoing construction projects-both private and public. A BMC official said some ongoing projects could be put on hold. “We plan to issue notices to all construction projects in our ward, asking them to put pollution mitigation measures in place,” he said.