Photochemical smog is a type of air pollution that is formed when sunlight reacts with certain pollutants in the atmosphere, such as nitrogen oxides (NOx) and volatile organic compounds (VOCs). It is characterized by the presence of high concentrations of oxidizing agents, such as ozone (O3), peroxyacyl nitrates (PANs), and nitric acid (HNO3). However, the statement that is incorrect is option 'c', which states that photochemical smog has a low concentration of oxidizing agents.

Incorrect statement: c) It has low concentration of oxidizing agent.

Explanation:
Photochemical smog is primarily composed of high concentrations of oxidizing agents, which are responsible for its harmful effects on human health and the environment. These oxidizing agents are formed through complex chemical reactions involving sunlight, NOx, and VOCs.

1. Formation of oxidizing agents:
- Sunlight breaks down nitrogen dioxide (NO2) into nitrogen monoxide (NO) and atomic oxygen (O).
- Atomic oxygen (O) then reacts with molecular oxygen (O2) to form ozone (O3), which is a highly reactive oxidizing agent.
- NO reacts with ozone (O3) to form nitrogen dioxide (NO2) and oxygen (O2).
- These reactions create a cycle that generates more ozone (O3) and nitrogen dioxide (NO2), leading to the accumulation of high concentrations of these oxidizing agents in the atmosphere.

2. Harmful effects of oxidizing agents:
- Ozone (O3) is a powerful respiratory irritant and can cause various health problems, including respiratory symptoms, reduced lung function, and increased susceptibility to respiratory infections.
- PANs and nitric acid (HNO3) can also cause respiratory and eye irritation.
- High levels of oxidizing agents can damage vegetation, including crops, by interfering with their ability to perform photosynthesis.

3. Control of photochemical smog:
- The formation of photochemical smog can be controlled by reducing the emissions of NOx and VOCs, which are the primary precursors of the oxidizing agents.
- This can be achieved through various measures, such as implementing stricter emission standards for vehicles and industries, promoting the use of cleaner fuels, and adopting pollution control technologies.
- Additionally, planting certain types of plants, such as pinus (pine) trees, can help in controlling photochemical smog by absorbing pollutants and releasing oxygen through photosynthesis.

In conclusion, the statement that photochemical smog has a low concentration of oxidizing agents is incorrect. Photochemical smog is characterized by the presence of high concentrations of oxidizing agents, including ozone, PANs, and nitric acid. Controlling the release of NOx, VOCs, and other pollutants, as well as promoting the plantation of certain plants, can help in reducing the formation of photochemical smog and its harmful effects.