1. Saudi Arabia.

2. Kuwait.

3. Bahrain.

4. Qatar.

5. UAE.

6. Oman.

7. Turkmenistan.

8. Libya.

9. Kazakhstan.

10. Trinidad & Tobago.

The 10 least toxic countries are listed as:

1. Kenya.

2. Tanzania.

3. Ethiopia.

4. Mozambique.

5. Cameroon.

6. Zambia.

7. Indonesia.

8. Zimbabwe.

9. Brazil.

10. Congo D.R.

It is important to note that the most toxic countries are majorly oil-producing countries while the least toxic countries are majorly countries with developing economies. Also to note is that Iceland was a notable omission in the list. Iceland's use of geothermal energy means that air pollution is very low and the country would therefore have ranked closer to Kenya.

So what makes Kenya the least toxic country in the world? Well, for starters, Kenya is big on renewable energy. Although oil was discovered in Kenya in the early 2010s, the country chooses to focus on more sustainable forms of energy such as geothermal energy, hydroelectric power, solar energy and wind energy. The renewable energy sector in Kenya is in fact the most active in Africa.

Additionally, Kenya is busy investing in different forms of transportation in order to reduce air pollution from road vehicles. The government is currently working on a project to make railway transport a norm in Kenya, a part of which features electric trains to be used in the city in order to reduce traffic jams and air pollution. The project is already well underway.