Tradable pollution permits
1. A pollution permit allows the owner to pollute up to a specific amount of pollution and the government controls how many permits there are so limits the maximum amount of pollution
2. Companies have to buy permits in order to pollute so, in an attempt to cut costs and increase profits, companies may use greener technology
3. Unused permits can be sold to other companies, hence why they are tradeable
4. Companies exceeding their limit of pollution will face legal action
5. As a fixed supply of permits is allocated, an increase in demand will lead to an increase in price for the permits, so companies will have more incentive to cut emissions by using green technology