All schools in Noida and Greater Noida were Thursday asked to hold classes online for students up to Class 8 till Tuesday amid alarming levels of pollution in the National Capital Region, according to an official order. The schools have also been told to hold classes for students of Class 9 to 12 online as far as possible, said the order issued by Gautam Buddh Nagar's District Inspector of Schools (DIOS) Dharmveer Singh.