story identification - Book with alien POV

A few years back, I found a book in the library. It was in the English section so I presume it was never translated into Serbian, which is my mother language. I also remember it had colorful covers and it looked so beat down and so old that it has to be from at least '70 or '80.

As for the plot I remember the following:

1. It was from an alien perspective


2. The main protagonist was an alien cop in search of drugs


3. The setting was on a human planet (I presume Earth, but I could be wrong since I don't remember whether the humans had colonized more planets)


4. I think the main protagonist had friends on said planet

Edit: I remembered two more things

1. Drug is something we use every day, possibly coffee, sugar or tobacco


2. Alien is annoyed how cold planet is

Answer

This sounds like Iceworld by Hal Clement:

The novel concerns an interplanetary narcotics agent who is forced to work on an incredibly cold world (from his point of view — the planet is in fact Earth), where he teams up with natives of the alien planet (humans) in his attempt to stop the smuggling of a dangerous drug (tobacco) to Sirius. Although the story involves both aliens and humans, it is told primarily from an alien perspective.