These four cities are showing the world innovative ways to go green.
1. You can buy bus tickets with plastic bottles in Surabaya, Indonesia.
2. Cockroaches are used to process food waste in Jinan, China.
3. Karachi in Pakistan will use animal dung to power its buses from 2020.
4. Copenhagen, Denmark, aims to be the world's first carbon-neutral capital by 2025 powered entirely by wind, sun, geothermal, waste, wood and biomass.
Source: World Economic Forum, 29 March 2019. Read the full article.