1.   Instead, once thickly forested areas sprouted luxury villas for Athenians seeking to migrate from the heavily polluted capital.

2.   A sweeping anti-smoking law was imposed in the highly polluted Indian capital on Sunday.

3.   Moscow itself is considered one of the most polluted capitals in the world where high levels of radioactivity have been recorded in many neighbourhoods.

4.   The Delhi government is planning to buy more CNG buses for the Delhi Transport Corporation as part of an aggressive clean air programme for the polluted capital.