Air fares for top five busy routes across the country have declined to their lowest levels in three years due to falling fuel prices and increase in capacity with the entry of new airlines like Vistara and AirAsia.

Average fare on the busiest Delhi-Mumbai route fell to Rs 4,984 in December this year compared to the same month in the last three years. Average fares on the route stood at Rs 7,000 in December 2014, Rs 9,502 in December 2013, and Rs 8,395 in December 2012.

Airlines usually see high passenger traffic in December every year due to Christmas and New Year holidays.

The top five busy routes across India are Delhi-Mumbai, Bengaluru-Delhi, Mumbai-Hyderabad, Delhi-Goa and Mumbai-Chennai.

Likewise, the average fare on the Delhi-Bengaluru route dropped to Rs 6,204 in December, which is much lower than the average fare of Rs 8,291 and Rs 9,453 in 2014 and 2013 respectively.

"The low fares during the current month this year is due to low ATF prices and increasing capacity which has come due to launch of new airlines," said Sharat Dhall, president, Yatra.com.

Prices of aviation turbine fuel, which account for 40-50% of the total operational cost of airline, have dropped 28.71% since December last year. The sharp decline was mainly due to a slump in global crude oil prices resulting from a supply glut.

The fall in airfares is also led by competitive pricing due to the entry of new carriers. Launched in January, Vistara now covers more than 10 destinations in the country.

"In the last year or so, we have seen 5-10% decline in the airfare across domestic as well as international airlines. On some sectors, like Mumbai-New York and New Delhi-New York, in the last year or so the peak decline in minimum fare has been as high as 71% and 56%, respectively," the Financial Express quoted Mohit Gupta, chief operating officer (Online), MakeMyTrip.com, as saying.

In contrast, fares on routes connecting smaller cities like from New Delhi to places like Ranchi, Raipur and Coimbatore have actually seen an increase.