Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions. It can have harmful effects on plants, aquatic animals and infrastructure.

The SO2 reacts with water in the clouds to form sulphuric acid and when the rain mixed with sulphuric acid and oxides of nitrogen it forms acid rain.

Acid Rain:
Acid rain is a type of rain that contains high levels of acidic pollutants. It is formed when emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) react with water, oxygen, and other chemicals in the atmosphere. These pollutants are released into the air primarily from the burning of fossil fuels, such as coal and oil, as well as from industrial processes and vehicle emissions.

Incomplete Combustion:
Incomplete combustion is a chemical reaction that occurs when there is insufficient oxygen available during the burning of a fuel. It results in the production of carbon monoxide (CO) and unburned hydrocarbons, which are released into the atmosphere as pollutants.

Harmful Effects:
The combination of acid rain and incomplete combustion can have several harmful effects on the environment and human health. Some of these effects include:

1. Environmental Damage: Acid rain can have detrimental effects on ecosystems, particularly on forests, lakes, and rivers. The acidic deposition can leach essential nutrients from the soil, making it difficult for plants and trees to grow. It can also cause the acidification of lakes and rivers, which can lead to the death of aquatic organisms.

2. Damage to Buildings and Infrastructure: Acid rain can corrode buildings, statues, and infrastructure made of limestone, marble, and other materials. The acidic deposition reacts with the minerals in these structures, causing them to deteriorate over time.

3. Air Pollution: Incomplete combustion releases pollutants such as carbon monoxide and unburned hydrocarbons, which contribute to air pollution. These pollutants can have detrimental effects on air quality and human health, leading to respiratory problems and other health issues.

4. Climate Change: Acid rain and incomplete combustion contribute to the release of greenhouse gases, such as carbon dioxide and methane, into the atmosphere. These gases trap heat in the Earth's atmosphere, leading to global warming and climate change.

5. Damage to Wildlife: Acid rain can harm wildlife by contaminating their habitats and food sources. It can also directly affect aquatic organisms, such as fish and amphibians, by altering the pH levels of their environments.

In conclusion, acid rain resulting from incomplete combustion has numerous harmful effects on the environment and human health. It is essential to reduce emissions of sulfur dioxide and nitrogen oxides to mitigate these effects and protect the planet.