People have polluted the river.
The river has been polluted by people.
Factories have emitted toxic gases.
Toxic gases have been emitted by factories.
Scientists have discovered new ways to reduce waste.
New ways to reduce waste have been discovered by scientists.
Deforestation has destroyed many animal habitats.
Many animal habitats have been destroyed by deforestation.
Governments have banned plastic bags in many countries.
Plastic bags have been banned in many countries by governments.
People have recycled millions of plastic bottles.
Millions of plastic bottles have been recycled by people.
Wildfires have damaged large forests.
Large forests have been damaged by wildfires.
Farmers have used pesticides to grow crops.
Pesticides have been used by farmers to grow crops.
Activists have organized environmental campaigns.
Environmental campaigns have been organized by activists.
Tourists have left trash on the beach.
Trash has been left on the beach by tourists.
The government has passed new environmental laws.
New environmental laws have been passed by the government.
People have installed solar panels in their homes.
Solar panels have been installed in homes by people.
Factories have reduced their carbon emissions.
Carbon emissions have been reduced by factories.
Consumers have demanded eco-friendly products.
Eco-friendly products have been demanded by consumers.
Authorities have protected endangered species.
Endangered species have been protected by authorities.
