A check on IndiGo's bookings portal showed tickets for a flight from Delhi to Mumbai in mid-January were being offered from Rs 1,896.
A check on IndiGo's website showed Rs 1,005 flight tickets on Bagdogra-Guwahati route were available for travel in January.
According to the IndiGo website, an "additional, non-refundable convenience fee of Rs 200 per passenger per sector will be levied on all online payments made through Net Banking/ Credit Cards/Debit Cards".
Low airfares have sparked a strong growth in air travel in India. Clocking a high double-digit growth for more than two years, India's domestic aviation market is one of the fastest growing in the world.
Domestic airlines carried 954 lakh passengers during January-October 2017, as against 814 lakh during the corresponding period the previous year, registering a growth of 17.30 per cent.
Meanwhile, IndiGo has said it will launch new flights on the Lucknow-Sharjah-Lucknow and Hyderabad-Sharjah-Hyderabad sectors from December 29, 2017. According to the airline, it will also connect Sharjah to Kolkata, Kochi, Goa, Tirupati, Rajahmundry, Patna, Mangalore, Visakhapatnam, Chennai, Raipur and Bhubaneswar through connecting flights.