Learn Dutch: Veel verkeer is slecht voor de leefbaarheid. - A lot of traffic is bad for livability.

It translates to 'livability' or 'quality of life' in a neighborhood. It is built from the stem of leven (to live). The suffix -baar creates the adjective leefbaar (livable), and adding -heid turns it into the abstract noun leefbaarheid (livability). It is a highly common word in Dutch news and politics.

Why do we use veel here instead of vele?

Because verkeer (traffic) is an uncountable noun. You only use the inflected form vele with plural, countable nouns to mean 'many' (such as vele auto's). For uncountable nouns meaning 'a lot of' or 'much', you must stick to the uninflected veel.

If I want to use this sentence with enerzijds (on the one hand), how does it affect the word order?

If you place enerzijds at the very beginning of the sentence, it takes up the first position. This triggers inversion, meaning the verb comes before the subject: Enerzijds is veel verkeer slecht voor de leefbaarheid. You would then follow up with an anderzijds sentence to provide the counterargument.