MUMBAI, Feb. 27 -- The fate of Mumbai Metro 7A or the Gundavali-Chhatrapati Shivaji Maharaj International Airport line is hanging in the air. During the construction of the line, the Mumbai Metropolitan Region Development Authority (MMRDA) discovered that the Airport Authority of India's (AAI) permission on the air funnel zone had been breached by a general consultant, and a revised nod has now been sought....