What are the disadvantages of fossil fuels ?

Explanation

### Step-by-Step Solution:

1. **Non-renewable Nature**:
- Fossil fuels are classified as non-renewable energy sources. This means that they are finite resources that will eventually run out. Once depleted, they cannot be replenished within a human timescale, taking thousands to millions of years to form again.

2. **Air Pollution**:
- The combustion of fossil fuels releases various pollutants into the atmosphere. This contributes significantly to air pollution, which can have harmful effects on human health and the environment.

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