- biodiversity: A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is under threat from humans.
- Toxic hotspots are locations where emissions from specific sources such as water or air pollution may expose local populations to elevated health risks, such as cancer. These emissions contribute to cumulative health risks of emissions from other sources nearby. Urban, highly populated areas around pollutant emitters such as old factories and waste storage sites are often toxic hotspots. (Wikipedia)