Pollution level using dictionaries

[klara]

Sorry for the delay, Monday came into play again and I had a ton of work @college.

Firstly, thank you everyone for your selfless help!

What I did now is:

def povprecje(januar):
    k = {}
    for day, data in januar.items():
        for city, pollution in data.items():
            if k[city]:
                k[city].append(pollution)
            else:
                k[city]=[]
                k[city].append(pollution)
                for pollution in k:
                    k[pollution] = sum(k[pollution])/len(k[pollution])
    return k

Somehow this kills the whole first definition since 0 tests pass when I run them! What the...??

What are your thoughts on this? Thank you in advance!