"During the action of descent stage thrusters and the consequent landing, a significant amount of lunar surficial epiregolith material got ejected, resulting in a reflectance anomaly or 'ejecta halo'," scientists at the National Remote Sensing Centre (NRSC) said in the paper. They estimated that the landing event had ejected 2.09 tonnes of lunar regolith over 108.4 square metre area.