I cycle from East London to Oxford Street every day, I found Plumelabs&#x27; data very strange: the air on the London Oxford street (the most polluted street: <a href="http:&#x2F;&#x2F;www.independent.co.uk&#x2F;environment&#x2F;air-pollution-in-londons-oxford-street-has-already-breached-the-legal-limit-for-the-whole-of-2015-in-9960277.html" rel="nofollow">http:&#x2F;&#x2F;www.independent.co.uk&#x2F;environment&#x2F;air-pollution-in-lo...</a>) is better than the Vienna&#x27;s average, which is considered to one of the cleanest city in Europe (<a href="http:&#x2F;&#x2F;www.euronews.com&#x2F;2015&#x2F;03&#x2F;31&#x2F;how-does-your-city-rank-in-european-air-pollution-survey&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.euronews.com&#x2F;2015&#x2F;03&#x2F;31&#x2F;how-does-your-city-rank-i...</a>). My nose tells the opposite.