Firstly, everybody knows that now at most of the world people can't go out. As a result of this the air pollution is decreasing. It is something good for the environment. But, we can't say the same for pets. As their owners can't go out, also they can't go out.

It is something bad for the health of the pets.
Secondly, nowadays nobody is thinking about buying clothes, going to zoo or hunting animals. So, people don't kill animals. It is also something good for the environment.
So, we understand that corona is mostly effecting the environment positively