The culture of India has been shaped by the long history of India, its unique geography and the absorption of customs, traditions and ideas from some of its neighbors as well as by preserving its ancient heritages, which were formed during the Indus Valley Civilization and evolved further during the Vedic age, rise and decline of Buddhism, Golden age, Muslim conquests and European colonization. India's great diversity of cultural practices, languages, customs, and traditions are examples of this unique co-mingling over the past five millennia.

India is also the birth place of several religious systems such as Hinduism, Jainism, Buddhism, and Sikhism. The various religions and traditions of India that were created by these amalgamations have influenced other parts of the world too.

The great number of languages in India have added to the diverse cultures and traditions at all levels. 1000, (if you count regional dialects and regional words, if you don't then 216) languages are spoken by a group of more than 10,000 people; however there are many others which are spoken by fewer than 10,000 people. Altogether, there are 415 living languages in India. The Constitution of India has stipulated the usage of Hindi and English to be the two official languages of communication for the Union Government. Individual state's own internal communications are done in the state's language. The two major linguistic families in India are those of the Indo-Aryan languages and the Dravidian languages, the former being largely confined to northern, western, central and eastern India and the latter to southern India. The next largest language family in India is the Austro-Asiatic language group, which contains the Munda languages of central and eastern India, the Khasian languages of northeastern India, and the Nicobarese languages of the Nicobar Islands. The fourth largest language family in India is the Tibeto-Burman languages, which are themselves a subgroup of the larger Sino-Tibetan language family.

Indian religions, a major form of world religions next to the Abrahamic ones, include Hinduism, Buddhism, Sikhism, Jainism. Today, Hinduism and Buddhism are the world's third- and fourth-largest religions respectively, with around 1.4 billion followers.

India is one of the most religiously diverse nations in the world, with some of the most deeply religious societies and cultures. Religion still plays a central and definitive role in the life of most of its people.

The religion of more than 80.4% of the people is Hinduism. Islam is practiced by around 13.4% of all Indians. Sikhism, Jainism and especially Buddhism are influential not only in India but across the world. Christianity, Zoroastrianism, Judaism and the Bahá'í Faith are also influential but their numbers are smaller. Despite the strong role of religion in Indian life, atheism and agnostics also have visible influence.

The Indian caste system describes the social stratification and social restrictions in the Indian subcontinent, in which social classes are defined by thousands of endogamous hereditary groups, often termed as jātis or castes. Within a jāti, there exist exogamous groups known as gotras, the lineage or clan of a person, although in a handful of sub-castes like Shakadvipi, endogamy within a gotra is permitted and alternative mechanisms of restricting endogamy are used (e.g. banning endogamy within a surname).

Although generally identified with Hinduism, the caste system was also observed among followers of other religions in the Indian subcontinent, including some groups of Muslims and Christians. The Indian Constitution has outlawed caste-based discrimination, in keeping with the socialist, secular, democratic principles that founded the nation. Caste barriers have mostly broken down in large cities, though they persist in rural areas of the country. Nevertheless, the caste system, in various forms, continues to survive in modern India strengthened by a combination of social perceptions and divisive politics.

In general terms, there are five principal divisions resulting from the caste:

• Brahmin - "scholarly community," includes the priests, scholars, law specialists, ministers, and diplomats.
• Kshatriya - "high and lower nobility" includes kings, noblemen, soldiers, and administrators.
• Vaishya - "mercantile and artisan community" includes merchants, shopkeepers, businessmen and farm owners.
• Shudra - "service-providing community" includes mostly manual and farm labourers in non-polluting occupations.

Namasté, Namaskar or Namaskaram is a common spoken greeting or salutation in the Indian subcontinent. Namaskar is considered a slightly more formal version than namasté but both express deep respect. It is commonly used in India and Nepal by Hindus, Jains and Buddhists, and many continue to use this outside the Indian subcontinent. In Indian and Nepali culture, the word is spoken at the beginning of written or verbal communication. However, the same hands folded gesture is made wordlessly upon departure. In yoga, namasté is said to mean "The light in me honors the light in you," as spoken by both the yoga instructor and yoga students.

Taken literally, it means "I bow to you". The word is derived from Sanskrit (namas): to bow, obeisance, reverential salutation, and respectand (te): "to you".

When spoken to another person, it is commonly accompanied by a slight bow made with hands pressed together, palms touching and fingers pointed upwards, in front of the chest. The gesture can also be performed wordlessly and carry the same meaning.

India, being a multi-cultural and multi-religious society, celebrates holidays and festivals of various religions. The three national holidays in India, the Independence Day, the Republic Day and the Gandhi Jayanti, are celebrated with zeal and enthusiasm across India. In addition, many states and regions have local festivals depending on prevalent religious and linguistic demographics. Popular religious festivals include the Hindu festivals of Diwali, Ganesh Chaturthi, Holi, Navratri, Rakshabandhan and Dussehra. Several harvest festivals, such as Sankranthi, Pongal and Onam, are also fairly popular. The Kumb Mela is a mass pilgrimage held every twelve years in four different locations attracting millions of Hindus. Certain festivals in India are celebrated by multiple religions. Notable examples include Diwali which celebrated by Hindus, Sikhs and Jains and Buddh Purnima which is celebrated by Buddhists and Hindus. Islamic festivals, such Eid ul-Fitr, Eid al-Adha and Ramadan, are celebrated by Muslims across India.