Environment

1. pollution

1.1. car fumes

1.2. rubbish

1.3. packaged food

1.4. traffic jams

1.5. throw away

2. renewable energy

2.1. solar power

2.1.1. solar panels

2.2. wind

2.3. hydroelectric power

2.4. bioenergy

2.5. geothermal energy

3. Green Transport

3.1. bicycle

3.2. bicycle lanes

3.3. public transport

4. Recycling

4.1. recycling bins

4.2. reuse

4.3. recycle

4.4. reduce