The Union Home Ministry on Saturday issued the Unlock 4 guidelines under which metro trains will be allowed to resume services from September 7 in a graded manner, while political, social and religious congregations of up to 100 people will be permitted from September 21. However, schools, colleges and other educational and coaching institutions will remain closed for students till September 30, with some relaxations for students of classes 9 to 12. Bars, which have been shut since March, will be allowed to open fro, September 1.