The correct answer is Deccan traps. Black Soil found in lava-covered areas is the most conspicuous.Those soils are often referred to as regur but are popularly known as "Black cotton soils" since cotton has been the most common traditional crop in areas where they are found.Black soils are spread mostly across the Deccan lava plateau and malwa plateau, where there is both moderate rainfall and underlying basaltic rock.They are rich in iron and highly moisture-retentive but poor in humus.Important PointsIndo Gangetic plains: The greater part of the plain is made up of alluvial soil, deposited by the three main rivers and their tributaries.Himalayan mountains: The major soils in the Himalayas are brown hill soil, sub-mountain soils, mountain meadow soil, and red loamy soils.Thar desert: Desert soil is mainly found in this area.