Illegal dumping is an act that has a serious impact on the environment.

Illegal dumping causes significant damage to the environment.

His actions exerted a great influence on our plans.

This problem is very serious.

Do you understand the seriousness of this problem?

His opinion had a big influence on my decision.

That news greatly influenced his opinion.

His actions were clearly illegal.

He crossed the border illegally.

We must strive to protect the environment of the Earth.