Navaratri[a] is a Hindu festival that spans nine nights (and ten days) and is celebrated every year in the autumn. It is observed for different reasons and celebrated differently in various parts of the Indian cultural sphere. Theoretically, there are four seasonal Navaratri. However, in practice, it is the post-monsoon autumn festival called Sharada Navaratri that is the most observed in the honor of the divine feminine Devi (Durga). The festival is celebrated in the bright half of the Hindu calendar month Ashvin, which typically falls in the Gregorian months of September and October.
In the eastern and northeastern states of India, the Durga Puja is synonymous with Navaratri, wherein goddess Durga battles and emerges victorious over the buffalo demon Mahishasur to help restore Dharma. In the northern and western states, the festival is synonymous with "Rama Lila" and Dussehra that celebrates the battle and victory of god Rama over the demon king Ravana. In southern states, the victory of different goddesses, of Rama or Saraswati is celebrated. In all cases, the common theme is the battle and victory of Good over Evil based on a regionally famous epic or legend such as the Ramayana or the Devi Mahatmya.
Celebrations include worshipping nine goddesses in nine days, stage decorations, recital of the legend, enacting of the story, and chanting of the scriptures of Hinduism. The nine days are also a major crop season cultural event, such as competitive design and staging of pandals, a family visit to these pandals and the public celebration of classical and folk dances of Hindu culture. Hindu devotees celebrate Navratri by fasting. But, fasting is not the correct way to please Maa Durga during Navratri or Shradha Navratri. Holy Bhagavad Gita has also denied fasting. It is clearly mentioned in Holy Bhagavad Gita Adhyay 6 Shlok 16 that this Yog Sadhna is not successful for those who sleep too much or don't sleep, nor for those who eat too much or don't eat,i.e., fasting. That's the reason we did not get the true fruits of Worship. On the final day, called the Vijayadashami or Dussehra, the statues are either immersed in a water body such as river and ocean, or alternatively the statue symbolizing the evil is burnt with fireworks marking evil's destruction. The festival also starts the preparation for one of the most important and widely celebrated holidays, Diwali, the festival of lights, which is celebrated twenty days after the Vijayadashami or Dussehra or Dashain.
According to some Hindu texts such as the Shakta and Vaishnava Puranas, Navaratri theoretically falls twice or four times a year. Of these, the Sharada Navaratri near autumn equinox (September–October) is the most celebrated and the Vasanta Navaratri near spring equinox (March–April) is the next most significant to the culture of the Indian subcontinent. In all cases, Navaratri falls in the bright half of the Hindu lunisolar months. The celebrations vary by region, leaving much to the creativity and preferences of the Hindu.
The other two Navratris are observed regionally or by individuals:
The Sharada Navaratri commences on the first day (pratipada) of the bright fortnight of the lunar month of Ashvini. The festival is celebrated for nine nights once every year during this month, which typically falls in the Gregorian months of September and October. The exact dates of the festival are determined according to the Hindu lunisolar calendar, and sometimes the festival may be held for a day more or a day less depending on the adjustments for sun and moon movements and the leap year.
The festivities extend beyond goddess Durga and god Rama. Various other goddesses such as Saraswati and Lakshmi, gods such as Ganesha, Kartikeya, Shiva, and Krishna are regionally revered. For example, a notable pan-Hindu tradition during Navaratri is the adoration of Saraswati, the Hindu goddess of knowledge, learning, music, and arts through Ayudha Puja. On this day, which typically falls on the ninth day of Navaratri after the Good has won over Evil through Durga or Rama, peace and knowledge is celebrated. Warriors thank, decorate and worship their weapons, offering prayers to Saraswati. Musicians upkeep their musical instruments, play and pray to them. Farmers, carpenters, smiths, pottery makers, shopkeepers and all sorts of tradespeople similarly decorate and worship their equipment, machinery, and tools of trade. Students visit their teachers, express respect and seek their blessings. This tradition is particularly strong in South India, but is observed elsewhere too. 
The festival is associated to the prominent battle that took place between Durga and demon Mahishasura and celebrates the victory of Good over Evil. These nine days are solely dedicated to Goddess Durga and her nine Avatars – the Navadurga. Each day is associated to an incarnation of the goddess:
Known as Pratipada, this day is associated with Shailaputri (literally "Daughter of Mountain"), an incarnation of Parvati. It is in this form that the Goddess is worshiped as the wife of Shiva; she is depicted as riding the bull, Nandi, with a trishula in her right hand and lotus in her left. Shailaputri is considered to be the direct incarnation of Mahakali. The color of the day is grey, which depicts action and vigor.
On Dwitiya, Goddess Brahmacharini, another incarnation of Parvati, is worshiped. In this form, Parvati became Sati, her unmarried self. Brahmacharini is worshiped for emancipation or moksha and endowment of peace and prosperity. Depicted as walking bare feet and holding a japamala and kamandal in her hands, she symbolizes bliss and calm. Blue is the color code of this day. Orange color depicts tranquility yet strong energy.
Tritiya commemorates the worship of Chandraghanta – the name derived from the fact that after marrying Shiva, Parvati adorned her forehead with the ardhachandra (lit. half-moon). She is the embodiment of beauty and is also symbolic of bravery. White is the color of the third day, which is a vivacious color and can pep up everyone's mood.
Goddess Kushmanda is worshiped on Chaturthi. Believed to be the creative power of the universe, Kushmanda associated with the endowment of vegetation on earth and hence, the color of the day is Red. She is depicted as having eight arms and sits on a Tiger.
Skandamata, the goddess worshiped on Panchami, is the mother of Skanda (or Kartikeya). The color of Royal blue is symbolic of the transforming strength of a mother when her child is confronted with danger. She is depicted riding a ferocious lion, having four arms and holding her baby.
Born to sage Katyayana, she is an incarnation of Durga and is shown to exhibit courage which is symbolized by the color Yellow. Known as the warrior goddess, she is considered one of the most violent forms of Devi. In this avatar, Kātyāyanī rides a lion and has four hands. She is a form of Parvati, Mahalakshmi,Mahasaraswati.
Considered the most ferocious form of Goddess Durga, Kalaratri is revered on Saptami. It is believed that Parvati removed her fair skin to kill the demons Sumbha and Nisumbha. The color of the day is Green. On Saptami, the Goddess appears in a white color attire with a lot of rage in her fiery eyes, her skin turns black. The white color portrays prayer and peace and ensures the devotees that the Goddess will protect them from harm.
Mahagauri symbolizes intelligence and peace. The color associated with this day is Peakcock Green which depicts optimism.
On the last day of the festival also known as Navami, people pray to Siddhidhatri. Sitting on a lotus, she is believed to possess and bestows all types of Siddhis. Here she has four hands. Also known as SriLakshmi Devi. The purple color of the day portrays an admiration towards nature's beauty.Sidhidatri is Parvati, the wife of Lord Shiva. Siddhidhatri is also seen as the Ardhanarishvara form of Shiva Shakti.It is believed that one side of Lord Shiva’s body is that of Goddess Siddhidatri. Therefore, he is also known by the name of Ardhanarishwar. According to Vedic scriptures, Lord Shiva attained all the siddhis by worshiping this Goddess.
Navaratri is celebrated in different ways throughout India. Some fast, others feast. Some revere the same Mother Goddess but different aspects of her, while others revere avatars of Vishnu, particularly of Rama. The Chaitra Navaratri culminates in Rama Navami on the ninth day, and the Sharada Navaratri culminates in Durga Puja and Dussehra.
The Rama Navami remembers the birth of Rama, preceded by nine days of Ramayana recital particularly among the Vaishnava temples. In the past, Shakta Hindus used to recite Durga's legends during the Chaitra Navaratri, but this practice around the spring equinox has been declining. For most contemporary Hindus, it is the Navaratri around the autumn equinox that is the major festival and the one observed. To Bengali Hindus and to Shakta Hindus outside of eastern and northeastern states of India, the term Navaratri implies Durga Puja in the warrior goddess aspect of Devi. In other traditions of Hinduism, the term Navaratri implies something else or the celebration of Hindu goddess but in her more peaceful forms such as Saraswati – the Hindu goddess of knowledge, learning, music, and other arts. In Nepal, Navaratri is called Dasain, and is a major annual homecoming and family event that celebrates the bonds between elders and youngsters with Tika Puja, as well as across family and community members.
The Navaratri is celebrated as the Durga Puja festival in West Bengal. It is the most important annual festival to Bengali Hindus and a major social and public event in eastern and northeastern states of India, where it dominates the religious life. The occasion is celebrated with thousands of temporary stages called pandals are built in community squares, roadside shrines and large Durga temples in West Bengal, Odisha, Jharkhand, Bihar, eastern Nepal, Assam, Tripura and nearby regions. It is also observed by some Shakta Hindus as a private, home-based festival. Durga Puja festival marks the battle of goddess Durga with the shape-shifting, deceptive and powerful buffalo demon Mahishasura, and her emerging victorious.
The last five days of Navratri mark the popular practices during Durga Puja. The festival begins with Mahalaya, a day where Shakta Hindus remember the loved ones who have died, as well the advent of the warrior goddess Durga. The next most significant day of Durga Puja celebrations is the sixth day, called Shashthi where the local community welcomes the goddess Durga Devi and festive celebrations are inaugurated. On the seventh day (Saptami), eighth (Ashtami) and ninth (Navami), Durga along with Lakshmi, Saraswati, Ganesha, and Kartikeya are revered and these days mark the main Puja (worship) with recitation of the scriptures, the legends of Durga in Devi Mahatmya and social visits by families to elaborately decorated and lighted up temples and pandals (theatre like stages). After the nine nights, on the tenth day called Vijayadashami, a great procession is held where the clay statues are ceremoniously walked to a river or ocean coast for a solemn goodbye to Durga. Many mark their faces with vermilion (sindooram) or dress in something red. It is an emotional day for some devotees, and the congregation sings emotional goodbye songs. After the procession, Hindus distribute sweets and gifts, visit their friends and family members.
In North India, Navaratri is marked by the numerous Ramlila events, where episodes from the story of Rama and Ravana are enacted by teams of artists in rural and urban centers, inside temples or in temporarily constructed stages. This Hindu tradition of festive performance arts was inscribed by UNESCO as one of the "Intangible Cultural Heritage of Humanity" in 2008. The festivities, states UNESCO, include songs, narration, recital and dialogue based on the Hindu text Ramacharitmanas by Tulsidas. It is particularly notable in historically important Hindu cities of Ayodhya, Varanasi, Vrindavan, Almora, Satna and Madhubani – cities in Uttar Pradesh, Uttarakhand, Bihar and Madhya Pradesh.
The festival and dramatic enactment of the virtues versus vices filled story is organized by communities in hundreds of small villages and towns, attracting a mix of audiences from different social, gender and economic backgrounds. In many parts, the audience and villagers join in and participate spontaneously, some helping the artists, others helping with stage set up, create make-up, effigies and lights.
The most famous Navaratri festival is organized at Katra in Jammu Province. It is an annual event promoted by Directorate of Tourism, Jammu and Shri Mata Vaishno Deviji Shrine Board. Hundreds of thousands of devotees pay their attendance at Katra for the festival.
Navaratri has historically been a prominent ritual festival for kings and military of a kingdom. At the end of the Navratri, comes Dussehra, where the effigies of Ravana, Kumbhakarna, and Meghanada are burnt to celebrate the victory of good (Rama) over evil forces on Vijayadashami.
Elsewhere, during this religious observance, goddess Durga's war against deception and evil is remembered. A pot is installed (ghatasthapana) at a sanctified place at home. A lamp is kept lit in the pot for nine days. The pot symbolizes the universe. The uninterrupted lit lamp symbolizes the Adishakti, i.e. Durga Devi.
In parts of Bihar, Durga Devi is revered during the autumn of Navaratri. In other parts, such near Sitamarhi close to Nepal border, the spring Navratri attracts a large Ramanavami fair which marks the birth of Lord Rama as well as a reverence for his wife Sita who legends place was born at Sitamarhi. It is the largest cattle trading fair and attracts a large handicraft market in pottery, kitchen, and houseware, as well as traditional clothing. Festive performance arts and celebrations are held at the local Hindu temple dedicated to Sita, Hanuman, Durga, and Ganesha.
Navaratri in Gujarat is one of the state's main festivals. The traditional celebrations include fasting for a day, or partially each of the nine days such as by not eating grains or just taking liquid foods, in remembrance of one of nine aspects of Shakti goddess. The prayers are dedicated to a symbolic clay pot called garbo, as a remembrance of the womb of the family and universe. The clay pot is lit, and this is believed to represent the one Atman (soul, self).