The World Health Organization attributes 23 per cent of all deaths to unhealthy environments; and this year, the top five risks cited in the World Economic Forum's Global Risk Report were all related to the environment.

In the context of COVID-19 infection, medical experts have warned that existing health problems, such as chronic obstructive pulmonary disease (COPD) or heart disease are critical determinants of lung damage risk; and results of a recent study indicate that long-term exposure to nitrogen dioxide-largely the result of burning fossil fuels-may be one of the most important contributors to COVID-19 fatality.

According to the World Health Organization, nearly one in three people suffers from malnutrition-and "a large part of the world's population is affected by diet-related diseases such as heart disease, stroke, diabetes and cancer."

A 2015 evaluation by the World Health Organization International Agency for Research on Cancer classified processed meat as carcinogenic, linking it to colorectal cancer; and in some countries, endocrine disrupting chemicals, which can produce adverse developmental, neurological and immune effects, can be found in plastic bottles and metal food cans.

By altering natural wildlife habitats for our own living, agriculture and industrial purposes, humans have reduced the natural "buffer zones" that would have separated them from wildlife, and created opportunities for diseases like COVID-19 to spill over from wild animals to people.