NEW DELHI : Severely hit by the COVID-19 pandemic, Delhi Metro has appealed to the Centre to revise the safety protocols to allow it to operate trains with at least full seating capacity to make up for the revenue shortfall.After being closed for over five months due to the pandemic, Delhi Metro on September 7 had resumed services with curtailed operation of the Yellow Line, before assuming full operations from September 12, all in compliance with the latest safety guidelines issued by the government.The 169-day closure of services from March 22 onwards had already financially hit the urban transporter and post resumption, regulated number of commuters further impacted its financial health.Sources on Friday said the DMRC has written to the.