Gwalior is a major city in the central Indian state of Madhya Pradesh; It is known as the City of Music having oldest musical gharana in existence. It lies in northern part of Madhya Pradesh and is one of the Counter-magnet cities. Located 313 kilometres (194 mi) south of New Delhi, the capital city of India and 446 kilometres (277 mi) from Bhopal, the state capital, Gwalior occupies a strategic location in the Gird region of India. The historic city and its fortress have been ruled by several historic Indian kingdoms. From the Alchon Huns in the 5th century AD to Gurjara Pratihara dynasty in the 8th century AD. It was passed on to Kachchhapaghatas in the 10th century AD. It fell into the hands of the Delhi Sultanate in 12th century AD, it was then passed on to the Tomars in the 13th century AD who were the vassal rulers of the Delhi Sultanate. The Mughal Empire conquered the city and its fortress in the 16th century AD. When the Mughal Empire was declining, it fell into the hands of Jat rulers, then to the Maratha in 1754, and lastly it was passed on to the Scindia Dynasty of Maratha Empire in early 18th century. In April 2021, It was found that Gwalior had the best air quality index amongst the 4 major cities in Madhya Pradesh.