A company or an institution acquires one carbon credit for destroying or sequestering a tonne of CO₂. There are other gases with stronger greenhouse effects than CO₂ – a gas called HFC-23 is worth 11,700 credits, a waste byproduct of HCFC-22 the most common refrigerant in the world. While HCFC-22 is ozone depleting, it is still in production in 16 plants in India and China. Some of these plants make about 50 per cent of their profits by selling the byproduct HFC-23. Read more here.