There are many environmental problems now, mostly due to human activities. For example, a problem spoiling the discharges from the factory. The incinerator to destroy, etc.
There are many environmental problems now. Mostly caused by human action, for example, the wastewater is released from the plant. The incineration to destroy etc.
Environmental problems are now. Is mainly caused by human activities, for example, the problem of operas at the was released from the factory waste incineration to destroy.