Around 64 per cent of the flights that were diverted from four metro cities -- Mumbai, Delhi, Bengaluru and Chennai --- last year were due to bad weather conditions, an official document stated.
According to estimates of the Ministry of Civil Aviation, in 2018, the worst affected airport due to "bad weather" conditions was Delhi airport as 213 flights were diverted because of it.
In 2017, just 111 flights were diverted from Delhi airport due to bad weather.
The document shows that total 796 flights were diverted from the airports of aforementioned four metro cities due to various reasons last year. Out of 796, the number of flights that were diverted due to bad weather stood at 510.
A total of 727 flights were diverted from the aforesaid four airports in 2017 for various reasons. Out of this, 502 flights were diverted because of bad weather.
Flight diversions due to "overhead congestion", also known as air traffic congestion, have increased at Bengaluru airport and Mumbai airport in 2018.
According to the document, while 37 flights were diverted last year from Bengaluru airport due to overhead congestion, such diversions were just seven in 2017. In 2016, this number stood at four only.
The number of flights that were diverted from Mumbai airport due to air traffic congestion increased to 41 in 2018 from 28 in 2017. In 2016, this number stood at seven only.
As the passenger traffic has been growing in double digit percentage terms for last few years, the number of flights have increased correspondingly, but the airport capacity at metro cities have not.
Therefore, the air traffic over airports of metro cities have become increasingly congested, as the flights have to wait in line to land safely.
According to the official document, the number of flights that have been diverted from airports of four metro cities -- Mumbai, Delhi, Bengaluru and Chennai -- due to air traffic congestion stood at 90 in 2017 and 134 in 2018.
Domestic air passenger volume grew 14.25 per cent to 171.25 million in fiscal 2019 over the previous year, according to data released by Indian aviation regular Directorate General of Civil Aviation.
In FY18, the passenger volume had clipped at a higher 18.3 per cent to 146.84 million.