A few words on environment management
The biggest problem in metro cities is dust & not vehicles pollution as Dust amount to 70 to 80 percent of air pollution.
Only method is to control this pollution is not to allow dust to come in contact with air
Dust on Roads can be cleaned or maybe removed by road-vacuuming method
Dust due soil can be removed by covering landfills with vegetation grass plantation etc.
& if this is not possible then soil may covered by spreading a layer of concrete (Bajri) cementing etc, a practice widely used by european countries.
Reforestation, Afforestation drive along roadsides is also an answer to reduce dust pollution.
The second major cause of air pollution is Industrial pollution which amount to 20 to 25 percent of total pollution
India has adequate environmental legislations for handling industrial pollution. Strict implimentation of the existing laws shall definitely reduce industrial pollution as well as pollution of water resources. Water harvesting & plantation of trees may be one of the preliminary condition for obtaining licence by medium & large industries. There should also be a legislation as regards adopting collective transportation means for their employees.
The next major reason is vehicular exaust which is about 7 percent of total pollutants ie pollution due to exhaust of cars two wheelers trucks etc
Provision of filters at exhaust ie filtering exhaust before letting it escape in air is an answer to this problem. The filtered pollutants may be recycled/used to manufacture products like ink, chemicals etc
Also a system similar to water methanol injection in aircraft exhaust (Only water may be used) engine may be designed in ground vehicles create conditions so that engine exhaust does not travel long distance in air. (This needs adequate research efforts) A system by utilising moisture present air thro a specially designed venturi to treat vehicular exhaust can be an option. The moist heavy dust particles on road may be cleaned/collected by vacuum cleaners and used as sand.
As we are aware Air comprise 70 to 80 percent of moisture A simple ventury design to trap air & let it pass thro a ventury and thereafter allowing ventury air to mix with vehicle exhaust shall not let pollutants travel to air for long due to high moisture. The ventury air may also be allowed to pass thro condenser of AC for cooling.
This low temp air may be used to cool IC engines which shall further increase thermal efficiency of engine.
As far as pollution due crop residual burning a system being adopted by south korea & european countries is very effective.Crop residual may be used to convert it into elecyrical energy as is being done by european countries.
Most of these efforts ie handling dust designing & development of system for handling vehicle exhaust require support of government agencies & qualified professional while reforestation planting activities can be undertaken by common people if adequate awareness is spread.
As population is growing so is the requirement of resources available on earth. Every individual needs food garments goggles shoes medicines etc etc and therefore more the population more is the demand of these products and more is industry More is depletetion of resources. A uniform population policy shall also help.