Domestic carrier IndiGo on Saturday cancelled 57 flights across its network, citing bad weather" at various airports, according to the airline's website. The airline has also cancelled 13 flights, as of now, for Sunday, with two of them for "operational reasons", and the remaining largely due to "forecasted bad weather". The Gurugram-headquartered IndiGo, which cancelled thousands of flights early this month on account of stricter norms related to the pilots' duty period and rest, have been cancelling some flights for more than one week now on account of "bad weather". The 57 flights cancelled on Sunday include from Chandigarh, Mumbai, Ahmedabad, Hyderabad, Amritsar, Bengaluru, Delhi, Gaya, Kolkata, Chennai, Jaipur and Pune, among others. Aviation regulator DGCA has announced the period between December 10 and February 10 next year as the official fog window this winter. As part of the DGCA fog operations (CAT-IIIB) norms, airlines have to mandatorily roster pilots who are trained