I was involved with a group that helped awareness of environmental problems such as pollution.

In the 80s and early 90s the plots also started to contain contemporary issues such as pollution.

The rivers face problems such as sand mining and pollution.

The reason could be lifestyle factors such as smoking, diet, or pollution.

Instead of just making people laugh, he often drew their attention to problems in American society, such as pollution, prejudice, and poor government.

Now that number is down to several hundred due to the threats to its habitat, such as pollution and other human action.

Unlike some other environmental problems such as pollution, the effect of an introduced species is not a single event.

Also, technology has negative effects on the environment such as pollution.

Spikes in human population can cause problems such as pollution, water crisis, and poverty.

Additional factors, such as habitat loss and pollution, may have also played a role.