
The Aryans, also known as the Indo-Iranians, were an Iranian people who either migrated into, or invaded and conquered, the Indian Subcontinent in circa 1700-1500 BC, bringing an end to the Indus Valley civilization. The Aryans branched out from the Indo-Europeans who originated from the Russian steppe and the Caucasus, and they migrated through the Tian Shan and Pamir Mountains and into the Indus Valley in approximately 1700 BC, when most of the Indus Valley civilization's cities disappeared after 200 years of decline. Conflict with the Aryans and diseases like leprosy and tuberculosis led to the downfall of the Indus civilization, and, while little physical evidence demonstrates a military conquest of India by the Aryans, the Hindu vedas tell stories of battles and forts, giving the archaeologist Sir Mortimer Wheeler the impression that the Aryans had invaded and conquered India in the same manner as the Kassites' conquest of Babylonia and the collapse of other Late Bronze Age civilizations. The Aryans proceeded to spread into northwestern India by 1500 BC, and their Sanskrit language and Indo-Iranian culture took root in the Indian Subcontinent. Whereas most ancient South Asians were evidenced to have been dark-skinned Dravidians who resembled the Andamanese people, the Aryans brought with them fair skin, creating a diversity of skin tones which persists in India. The Aryan culture played a major role in the formation of Northern Indian culture, but, during the late 19th and early 20th centuries, the legacy of the Aryans was corrupted by white supremacists who claimed that the "white Aryan race" was responsible for all of the achievements of the ancient civilizations, and that an "Indo-Germanic" race (essentially people of Scandinavian and other Germanic heritage) was the superior "master race". The term "Aryan" thus became associated with the racial policies of Nazi Germany after the 1930s and 1940s and became an unpopular term, with the term "Indo-Iranian" becoming more popular in the aftermath of World War II. During the 21st century, several Indian news outlets challenged the idea of an Aryan invasion, with the Indian digital news publication Scroll theorizing that opposition to the theory came from the BJP government's nationalist "Hindutva" ideology, which supported racial nativism and rejected "India's incredible diversity."