Specifically on electric cars and hybrids, mining, refining, and processing the elements in the batteries is pretty nasty business, as is the recycling / disposal of them once they're flat. There are tons of EVs and hybrids out there, and I see this becoming a huge e-waste problem in the near future. Note that Tesla is/was doing something to make the part after they're discarded less bad: https://www.teslamotors.com/blog/mythbusters-part-3-recyclin...