It's because there are other sources of pollution far worse than cars.

For example cargo ships:

https://newatlas.com/shipping-pollution/11526/

> If those emissions standards are so rigorous why is climate change still happening?

Mostly because of the Chinese industry. Also coal and gas electricity generation. Nuclear power is the solution.

> Now divide by the number of passengers and try again.

Doesn't work like that. You can't divide noise. There's a threshold level.

Do you think 1 car generates the same amount of noise as 100 cars? 1 tram is not a replacement for 1 car.