Months after N Chandrasekaran took over as chairman of Tata Sons nine years ago, one of the first strategic projects that landed on his desk was the group's proposed acquisition of a stake in GMR Airports. Back then, the Tata Group had two operating airlines in its portfolio — Vistara and AirAsia India. Rules framed during the 2005 privatisation of Delhi and Mumbai airports stipulated that airport operators could not hold more than a 10% stake