Well, there are many evidence-based answers available in published research. Resource allocation, policy/regulation, and awareness raising are among the broader answers. Noise, air, water pollution should be the primary targets and indoor vs.outdoor pollution will have to be considered separately by the strategies designed to address pollution. Here is a resource to consider for reading:

http://cdrwww.who.int/mediacentre/events/H&SD_Plaq_no9.pdf 

Strict regulations. Example: Singapore.

Strong policy/regulation and the strict implications are the main way to prevent the environmental pollution. The awareness building will be the additional steps. 

Save greenery, Lake and Ponds. Perfect drainage system. Maximum utility of rain water -perfect storage arrangements. Control urbanisation and industrialisation. Protect water sheds. Overall mass awareness.

Strict effluent disposal standards for wastewater and strict regulations for air emissions. Best regards. 

Dear Dr. Shah

Thank you for your valuable answer. I do agree with you and think that one of the most important aspects is the awareness raising regards to the various environmental pollution sources...

Regards,

Ata

Dear Md Saiful Islam 

Thanks for your contribution. I think that strict regulations are important but not the only way to prevent the environmental pollution. In fact, environmental awareness is an integral part of the movement’s success toward preventing the environmental pollution.

Regards,

Ata

Dear Dr. Kumar

I do appreciate you so much for your valuable answer.

Regards,

Ata

Dear Nabeel

Thank you very much for your contribution. As I stated above, strict regulations are important but not the only way to prevent the environmental pollution...

Regards,

Ata

The answer can be shortened by the fact that countries are rebuilding people in accordance with a vision of respect for the environment , and studying environmental awareness in schools.

Dear Dr. Osman

I do appreciate you for your valuable contribution.

Regards,

Ata