Indian carrier IndiGo has signed a term sheet with France’s ATR to buy 50 72-600 aircraft, worth more than $1.3bn at list prices.

The deal has the option to reduce the number of aircraft deliveries based on certain conditions.

Scheduled to enter service by the end of this year, the new aircraft will help IndiGo in expanding its regional presence.

The aircraft is also expected to help the Indian Government’s new UDAN regional connectivity scheme (RCS), which seeks to boost economic development, employment and tourism by connecting small and remote cities across the country.

With more than 20% annual growth, India’s domestic aviation market is estimated to become the world’s third largest market by 2020.

"We are embarking on a journey to build a nation-wide regional network and connect cities that have not benefitted from the growth in Indian aviation."

As part of the RCS, India will receive 100 new airports within the next two to three years, and airlines will get financial support and other incentives to make air travel affordable.

IndiGo president Aditya Ghosh said: “In support of our Honourable Prime Minister Narendra Modi’s UDAN vision, we are embarking on a journey to build a nation-wide regional network and connect cities that have not benefitted from the growth in Indian aviation.

“The ATR's low operating costs will help us build a large regional air travel network with reasonable fares. These aircraft will feature modern cabin interiors, thus making the flight a comfortable experience for our passengers.

“The ATR’s outstanding operational versatility, along with their capabilities to land in remote airports with limited infrastructure will help us manage our operations efficiently.”

ATR’s 72-600 aircraft has the ability to accommodate between 68 and 78 passengers, and is equipped with Pratt & Whitney engines.