Indian citizens, without transit or regular Schengen visas, are unable to fly to the UK through European Union airlines like Lufthansa, KLM and Air France as they are stopped at the origin airports in India itself.
As the UK is no longer part of the European Union, it has, post Brexit, made mandatory of for non-EU citizens to get a transit Schengen visa in order to fly to the UK on transit flights operated by its airlines.
Schengen visa is a short-term visa that allows its holder to travel freely throughout the Schengen area, which covers 26 EU countries or "Schengen States" without border controls between them.
The move took place on January 1 last year.
Non-EU citizens can fly to the UK without transit or regular Schengen visa only through non-stop flights or by one stop flights only through Gulf countries or Switzerland. The EU rule does not apply for Switzerland as it is not a member of the Union.
However, there are several services which fly directly to the United Kingdom.
After India resumed scheduled international flights, foreign airlines have started offering one-stop connections between India and the rest of the world.
Following the Russia-Ukraine conflict, this one-stop business has also increased significantly.
Last year, Air India had announced non-stop flights between India and the UK.