Malwa region occupies a plateau in western Madhya Pradesh and south-eastern Rajasthan (between and ), with Gujarat in the west. The region includes the Madhya Pradesh districts of Agar, Dewas, Dhar, Indore, Jhabua, Mandsaur, Neemuch, Rajgarh, Ratlam, Shajapur, Ujjain, and parts of Guna and Sehore, and the Rajasthan districts of Jhalawar and parts of Kota, Banswara and Pratapgarh. Malwa is bounded in the north-east by the Hadoti region, in the north-west by the Mewar region, in the west by the Vagad region and Gujarat. To the south and east is the Vindhya Range and to the north is the Bundelkhand upland. The plateau is an extension of the Deccan Traps, formed between 60 and 68 million years ago at the end of the Cretaceous period. In this region the main classes of soil are black, brown and bhatori (stony) soil. The volcanic, clay-like soil of the region owes its black colour to the high iron content of the basalt from which it formed. The soil requires less irrigation because of its high capacity for moisture retention. The other two soil types are lighter and have a higher proportion of sand. The average elevation of the plateau is 500 m. Some of the peaks over 800 m high are at Sigar (881 m), Janapav (854 m) and Ghajari (810 m). The plateau generally slopes towards the north. The western part of the region is drained by the Mahi River, while the Chambal River drains the central part, and the Betwa River and the headwaters of the Dhasan and Ken rivers drain the east. The Shipra River is of historical importance because of the Simhasth mela, held every 12 years. Other notable rivers are Parbati, Gambhir and Choti Kali Sindh. Due to its altitude of about 550 to 600 meters above mean sea level, the region has comparatively cool evenings against the hot days during the summer season. Even if the day temperature reaches 42 to 43 degrees Celsius, the night temperatures are always in range of 20 to 22 degrees making the climate much cooler than the other areas of the region. The cool morning wind, the karaman, and an evening breeze, the , make the summers less harsh. The term Shab-e-Malwa, meaning dusk in Malwa (from shab, Urdu for night), was introduced by the Mughals. The year is popularly divided into three seasons: summer, the rains, and winter. Summer extends