An experiment in Gujarat yields impressive results.

The Economist
October 10, 2024

...A new study suggests the strategy is working. Nicholas Ryan of Yale University and his collaborators have used a randomised controlled trial to measure whether the mechanism reduces pollution. They find that plants that have taken part in the trading scheme have emitted 20-30% less than those that have not. The programme, which is proving popular, has given firms clarity and flexibility, says Mr Ryan. 

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