<Ul> <Li> Winter </Li> <Li> Spring </Li> <Li> Summer </Li> <Li> Autumn </Li> </Ul> <Tr> <Th> Tropical seasons </Th> </Tr> <Tr> <Td> <Ul> <Li> Dry season </Li> <Li> Wet season </Li> </Ul> </Td> </Tr> <Ul> <Li> Dry season </Li> <Li> Wet season </Li> </Ul>

What are the causes of air pollution wikipedia