1.   The boy could not breathe in the choking air and began coughing and panicking.

2.   The choking air pollution from leaded gasoline fumes can be troubling for people with respiratory problems, particularly in the big cities such as Tehran and Isfahan.

3.   The other pressing issue was the choking air pollution that blanketed much of Southeast Asia, shutting factories and sparking health alerts in Indonesia, Singapore and Malaysia.

4.   Greece now has to deliver on its promises to slash choking air pollution and chaotic traffic by completing a new metro on time.

5.   Governing a city replete with traffic jams, choking air pollution and runaway crime is hardly a dream job.

6.   Paralysing traffic and choking air pollution now plague many Asian cities.