1. our environment is being seriously polluted and we need to protect it from now.
2. air, water, light, soil,... pollution
Air: Air pollution results when the by-product of an activity makes chemicals airborne. Close to Earth’s surface, sulfur dioxide (SO2) interacts with the water cycle in the atmosphere to produce acid rain or other forms of acid deposition downwind. Nitrogen oxides (NOx) in vehicle exhaust and sunlight combine to form photochemical smog.
Light:Light pollution is unwanted or excessive light caused by streetlights and illuminated buildings, towers, and other structures. Light pollution changes nighttime visibility of natural features, disorienting migratory animals and fostering bird collisions with lighted towers and buildings.
Thermal: Thermal pollution is the addition of heat to a cool environment, and it is caused by water or air used as cooling fluids in power plants and manufacturing that becomes heated in the process. Heated cooling water from power plants may be 15 ˚C (27 ˚F) hotter than lake or stream water, which increases metabolic rates in fishes and reduces the amount of dissolved oxygen that the water may hold. In extreme cases, it can be hot enough to burn animal tissues.
3. 

• Water pollution brings about a dangerous effect on human health as well as on the ecosystem.

There are other emitted "pollutant" gases from industrial processes and human activity. Some are more "potent" than carbon dioxide, but smaller in quantity. All of them have the potential to raise the average global temperature by retaining more of the heat energy from the sun than the atmosphere would retain without them in it.
4 Air: Air pollution results when the by-product of an activity makes chemicals airborne. Close to Earth’s surface, sulfur dioxide (SO2) interacts with the water cycle in the atmosphere to produce acid rain or other forms of acid deposition downwind. Nitrogen oxides (NOx) in vehicle exhaust and sunlight combine to form photochemical smog.
5. I think that's the light pollution. Because VN is one of the countries with strong industrial development so the lights in VN surely gets brighter. 
6. Soil : we have to correct the mistakes that man has made towards nature. We must propagate to people not to litter indiscriminately, to pick up trash in the neighborhood, not to litter indiscriminately, to stop factory activities, and to refrain from using motorbikes and cars in traffic. Especially we have to raise people's awareness.