Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Brainstorm 3 possible solutions to the following problem: 

Pollution levels in a heavily populated city have increased.

### Response:
1. Subsidize public transportation to reduce the number of cars on the road. 
2. Incentivize businesses to switch to renewable energy sources.
3. Implement stricter regulations on industrial pollution.