Punjab (; Gurmukhi: ਪੰਜਾਬ; Shahmukhi: پنجاب; Punjabi: [pənˈdʒaːb] (listen); also romanised as Panjāb or Panj-Āb) is a geopolitical, cultural, and historical region in South Asia, specifically in the northern part of the Indian subcontinent, comprising areas of eastern Pakistan and northwestern India. Punjab's major cities are Lahore, Faisalabad, Rawalpindi, Gujranwala, Multan, Ludhiana, Amritsar, Sialkot, Chandigarh, Shimla, Jalandhar, Gurugram, and Bahawalpur. Punjab grew out of the settlements along the five rivers, which served as an important route to the Near East as early as the ancient Indus Valley civilization, dating back to 3000 BCE, and had numerous migrations by the Indo-Aryan peoples. Agriculture has been the major economic feature of the Punjab and has therefore formed the foundation of Punjabi culture, with one's social status being determined by land ownership. The Punjab emerged as an important agricultural region, especially following the Green Revolution during the mid-1960s to the mid-1970s, and has been described as the "breadbasket of both India and Pakistan."Besides being known for agriculture and trade, the Punjab is also a region that over the centuries has experienced many foreign invasions and consequently has a long-standing history of warfare, as the region is vulnerably situated on the principal route of invasions through the northwestern frontier of the Indian subcontinent, including those of Persians, Macedonians, Scythians, Parthians, Kushans, Huns, Arabs, Turks, and Mongols until the eighteenth century which promoted a lifestyle that entailed engaging in warfare to protect the land, with the Marathas, Durranis and British invading the region in subsequent decades. The boundaries of the region are ill-defined and focus on historical accounts and thus the geographical definition of the term "Punjab" has changed over time. In the 16th century Mughal Empire it referred to a relatively smaller area between the Indus and the Sutlej rivers. In British India, until the Partition of India in 1947, the Punjab Province encompassed the present-day Indian states and union territories of Punjab, Haryana, Himachal Pradesh, Chandigarh, and Delhi, and the Pakistani regions of Punjab, and Islamabad Capital Territory. It bordered the Balochistan and Khyber-Pakhtunkhwa regions to the west, Kashmir to the north, the Hindi Belt to the east, and Rajasthan and Sindh to the south. The predominant ethnolinguistic group of the Punjab region is the Punjabi people, who speak the Indo-Aryan Punjabi language. Punjabi Muslims are the majority in West Punjab (Pakistan), while Punjabi Sikhs and Punjabi Hindus are the majority in East Punjab (India). Other religious groups are Christianity, Jainism, Zoroastrianism, Buddhism, and Ravidassia.