Introduction:
The Indian party system witnessed a transition to a multi-party system during the period of 1977-1980. This transition was a significant development in Indian politics, marking the end of single-party dominance and the emergence of multiple political parties.

Explanation:
During the initial years after India's independence in 1947, the Indian National Congress (INC) enjoyed a dominant position in the Indian party system. The INC, led by Jawaharlal Nehru, held a strong majority in the Parliament and formed the government at the center. This period from 1952 to 1964 is known as the "Congress System" era.

Emergence of Opposition Parties:
1. In the 1950s and 1960s, several regional and opposition parties started gaining ground and challenging the dominance of the Congress party.
2. The Communist Party of India (CPI) emerged as a significant opposition party, particularly in states like Kerala and West Bengal.
3. Other regional parties like the Dravida Munnetra Kazhagam (DMK) in Tamil Nadu, the Akali Dal in Punjab, and the Telugu Desam Party (TDP) in Andhra Pradesh also gained popularity.

Indira Gandhi's Split from Congress:
1. The period from 1964 to 1977 witnessed political turbulence and the split within the Congress party itself.
2. In 1969, Indira Gandhi, the daughter of Jawaharlal Nehru, took over as the Prime Minister of India. However, she faced opposition from within the Congress party.
3. In 1971, Indira Gandhi led the Congress party to victory in the general elections, but her authoritarian style of governance and the imposition of emergency in 1975 led to further discontent.

Post-Emergency Period:
1. The imposition of emergency in 1975 and the subsequent public backlash against Indira Gandhi's government led to a significant realignment of political forces in India.
2. In 1977, the opposition parties formed a coalition called the Janata Party, which emerged victorious in the general elections, ending the Congress party's uninterrupted rule.
3. This marked the beginning of the transition to a multi-party system, with the emergence of various political parties and coalitions challenging the dominance of the Congress party.

Conclusion:
The period from 1977 to 1980 witnessed a significant transition in the Indian party system, as the single-party dominance of the Congress party gave way to a multi-party system. This transition was a result of various factors, including the emergence of regional and opposition parties, the split within the Congress party, and the public backlash against the authoritarian rule of Indira Gandhi.