Cities with the most clean air:
1. Helsinki
2. Hobart 
3. Reykjavik 
4. Vienna 
5. Victoria 
6. Stockholm 
7. The Hague 
8. Luxembourg 
9. Zurich 
10. Gothenburg
87. Berlin 
99. Tokyo 
160. London 
161. NY 
222. Istanbul 
300. Delhi 
