Question

what measures are necessary for arresting pollution

Answer 1

1) Afforestation
2) Minimising the use of vehicles

Answer 2

The following are some of the steps that've already been on the charts for long, but implementing them has taken a back seat:

Introducing newer public transport vehicles that run on CNG. (This is already present in some metropolitan cities, but needs more penetration nationwide.)
Upgrading the existing railways with electric engines in place of the present Diesel engines.
Promoting the use of solar power for all public lighting.
Making the garbage disposable system as efficient as the Mumbai dabbawallas.
Doing a mandatory check to ensure that trucks and buses comply with the motor vehicles act on pollution.
Hiring a private company to keep the city streets clean.