Group 1 - The core viewpoint of the article highlights the rising PM2.5 concentration in Liuzhou city and surrounding areas, reaching severe pollution levels due to regional pollution transport and local accumulation effects starting from January 17 [1] - On January 17, the PM2.5 concentration decreased to light or moderate pollution levels in the afternoon due to improved sunlight conditions and decreased air stability, but is expected to rise again at night due to local pollution sources [1] - The article provides a recommendation for vulnerable groups, including children, the elderly, and individuals with heart or respiratory diseases, to reduce outdoor activities and wear protective gear during pollution periods [3]

Environmental Concerns - Toxic smog has returned to Hanoi, Vietnam [1] - Authorities are urging residents with respiratory conditions to stay indoors due to the smog [1]

Environmental Concerns - Solving air pollution issues in the country may lead to increased temperatures [1]

Environmental Concerns - Solving the country's air pollution problem may lead to increased temperatures [1]

Environmental Concerns - Air pollution is a significant issue in the country [1] - Solving air pollution may lead to increased temperatures [1]

If its awful air pollution is ever solved the country will get even hotter https://t.co/Q15yTZ2GHG ...

Health Impact - Study finds wood burning linked to nearly 2,500 U_K_ deaths a year [1]

Delhi's air has become toxic once again https://t.co/wOgBPIt6C7 ...

If its awful air pollution is ever solved the country will get even hotter https://t.co/RWCnjlfweT ...

Toxic haze in Delhi despite 'green' Diwali https://t.co/auQD8ix6WW ...