What are the main industrys that produce a lot of negative externalities?

It just means "negative impact" while not being involved in the transaction.
There are many many examples...

Let's say the local bars were to give people free rides home when they are intoxicated. A negative externality is that the taxi business is less profitable, because less intoxicated people catch a cab.

Positive externalities are the exact opposite. Something good happens


BTW its difficult to quantify externalities