It is followed by water pollution (71 percent), food contamination (62 percent), plastic waste pollution (59 percent) and deforestation (55 percent), according to a survey done by market research firm Q&Me which interviewed 792 Vietnamese citizens aged 18-49.

Other issues of leading concern were global warming (46 percent), ozone depletion (32 percent) and wildlife extinct (30 percent).

Eighty-four percent of Vietnamese respondents paid higher attention to environmental issues than the previous year while 14 percent stayed on the same, the survey report said.

Females and the older group tend to be more concerned about environmental issues than males and the younger people, it added.

Sixty-seven percent of Vietnamese get information about the environment via TV, followed by Facebook (60 percent) and online news sites (56 percent).

Among most common actions to protect the environment were purchase of eco-friendly products (67 percent), savings (66 percent) and saving electricity (63 percent).

Air pollution in Hanoi and HCMC has become a hot topic in recent years.

Authorities admit that air quality in both cities has worsened in recent years due to exhaust fumes, factory smoke and construction dust.

Vietnam suffers an estimated $10.8- $13.2 billion worth of economic loss due to ambient air pollution each year, or equivalent to 5 percent of GDP, according to official data.

Vietnam ranked fourth in the number of pollution-linked deaths in the Western Pacific, with an estimated 71,365 Vietnamese people losing their lives to pollution, including 50,232 to air pollution, in 2017, the latest year for which data was available, according to the Pollution and Health Metrics report by Global Alliance on Health and Pollution.