LONDON—European buyers are increasing shipments of coal from across the globe against a backdrop of a proposed European Union ban on Russian imports and the scramble to relieve tight gas supplies, according to data and shipping sources. The European Commission on Tuesday proposed new sanctions against Moscow over its invasion of Ukraine, including a ban on buying Russian coal and on Russian ships entering EU ports. The new restrictions come at a time of uncertainty about future gas deliveries from Russia to the EU later this month after the Kremlin’s demand that buyers start paying Russian gas giant Gazprom in roubles. In March, European countries imported a total of 7.1 million tonnes of thermal coal, which is used in power and heat generation, a 40.5 percent increase year-on-year and the highest level since March 2019, analysis from shipbroker Braemar ACM, based on ship tracking data, found. “Despite Russian coal shipments …