|There are some unnecessary words
in the first sentence. Let's look at it.
The greenhouse effect is one of the phenomena caused by industrial pollution.
We can shorten one of the phenomena to a phenomenon or even leave out the whole phrase. Let's try it both ways.
The greenhouse effect is a phenomenon caused by industrial pollution.
The greenhouse effect is caused by industrial pollution.
Which do you like better? Both of these sentences are fine and you can take your choice.