Amid growing concern over spreadof coronavirus, Chief Minister Uddhav Thackeray said on Friday that all workplaces in major cities in Maharashtra, including Mumbai and Pune, will remain closed till March 31.This will be applicable in Mumbai, MMR Region, Pune, Pimpri Chinchwad and Nagpur, Thackeray told reporters here.Government offices will operate at 25 per cent attendance, he said.