Correct my mistakes please.

There is a plan which will be of spending 760 billions dollars/yuan/euros on pollution control in Beijing.

In next 3 years, starting from reduce the release of PM2.5.

(I dont understand, here are differents corrections) 

The plan will start off in 3 years from now and its aim is to reduce the release of PM2.5.

Within the next the 3 years the release of PM2.5 will have started to redeace.

This new plan's aim is to reduce 4 major 4 types of pollution sources, including this includes exhaust release from approximately 5 millions motor vehicles, nearby fuel-burning, sand storm and local construction dust.

There are 85 billions dollars/yuan that will be spend spent on the updating and building of sewage and rubbish equipment.

Besides, the government has invested 30 billions yuan to on reforestation in for the next 3 years.

To improve the environment, the city government (still == do you mean also?) plans to build a number of water-cycle factoryies, and forbid construction illegally  illegal constructions / building illegaly.

In addition to, there is are more severe punishments to for toxic emission.

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This is pretty good, there are small mistakes that cant go unnoticed, but you get the message across. 

I personnaly find this topic very interesting. Pollution is our worst and major problem for our modern industrial way of life. That is especially true for China, on which the entire world relies for its manufactured goods, and add on to that the fact that China's population density is a lot stronger than elsewhere. 

Correct my mistakes please.

There is a plan which will be spent(cost) 760 billions on (in)pollution controlled in Beijing. In next 3 years, starting from reducing the release of PM2.5. This new plan aims to reduce  4 major types of pollution sources, including exhaust released from approximately 5 millions motor vehicles, nearby fuel-burning, sand storm and local construction dust. There are 85 billions(USD OR RMB) will be spent on updating and building of sewage and rubbish equipment. Besides, government has invested 30 billions to forestation in next 3 years. To improve environment, city government still plan to build a number of water-cycle factories, and forbid construction illegally. In addition to, there is more severe punishments to toxic emission.

If pay more attention to some details,you will do better！Anyway,you done a great job!