The world’s coal market experienced an unexpected revival in 2017, according to an annual energy round-up from BP, an oil firm.

The uptick was driven partly by a resurgence of demand for coal in China, which increased by 0.5% year on year, after falling for three consecutive years.

Although China is attempting to diversify away from the dirtiest fuels, it used more coal to satisfy its growing electricity demand. The global power sector still remains heavily dependent on coal, too.

Despite growth in the use of renewables in recent years, and efforts to shift power generation away from coal, it accounts for around two-fifths of the total, the same share as two decades ago.