Last week the government announced plans to restore 90% of that to safely usable levels by 2020. Officials estimate that the clean-up might cost more than $1tn. The cost of reaching the environmental targets could run as high as $300bn a year for the five years, and China’s government might only pay for about 15% of the bill. The Financial Times reports the shortfall is likely be filled in part by increased use of so-called green bonds — debt instruments issued for projects explicitly aimed at environmental applications. In the first quarter of 2016 about $17bn were issued globally, nearly three times as much as a year earlier. Almost half of this came from China. Moody’s estimates that global green bond issuance could total $70bn in 2016.