The Supreme Court on Thursday asked the Central government to formulate a plan to curb pollution in other cities along with the national capital.A division bench headed by Justice Madan B. Lokur wondered why the Delhi-NCR region was receiving special treatment when air pollution in Patna and Raipur was even worse.The Central government told the court that it has been working on a comprehensive action plan to deal with air pollution nationwide and will finalise it soon, adding that it has notified the plan.It said the Central Pollution Control Board is to issue directions to respective authorities of the Central government, Delhi and National Capital Region on Thursday to take steps as per the timeline laid out in the action plan.The bench was hearing a PIL filed by environmentalist M.C. Mehta on various aspects of pollution.