Around one-third of all air passengers had to pay extra money for seats on a flight in the last 12 months as the free seat option was not available, according to a survey.

The survey, conducted by online platform LocalCircles, was based on 30,000 responses from individuals across 351 districts.

As per the survey, some 60 per cent of the respondents also batted for capping the number of paid seats at 30 per cent of the total seats.

The Directorate General of Civil Aviation had in 2015 announced unbundling of services, allowing Indian airlines to charge all of their fliers extra for choice of specific seats, luggage and use of airline lounges, among other facilities.

"One in every third person surveyed said that the airline they booked did not give the option to secure a free seat," the survey said.

Some consumers prefer to reserve seats as per their choice which can be availed by paying an extra Rs 200-1,500, especially for seats in the front and emergency rows as they offer more legroom.

This means that consumers can reserve their preferred seats on the plane by paying extra during the booking or web check-in.

In case the consumer doesn't wish to purchase a preferred seat, airlines are supposed to ensure that there are enough free seats available for them to select from during the web check-in.

"Many consumers have been complaining on LocalCircles and other social media platforms about some airlines still charging a fee for allotment of all seats on the plane and there is not a single seat kept for free allocation. However, some airlines continue to charge consumers extra for all seats on the plane," it said.

According to the platform, during its survey, it was also found that 2 in every three consumers, who booked flights in the last 12 months, paid extra fee for reserving a seat once or more while another 34 per cent of them said they had to pay every single time.

One in three of those consumers who booked flights say the airline was charging extra fee for allotment of each seat on the plane.

"In summary, over 1 in 3 consumers who booked flights in the last 12 months say the airline was charging extra fee for allotment of each seat on the plane.

"Furthermore, 2 in 3 consumers...say they paid an extra fee for reserving a seat once or more. Of whom, 34 per cent said they had to pay every single time," LocalCircles said.