After Hinduism, the religion in India with the maximum followers is Islam. Islam is the second-largest religion in India, comprising around 14.2% of the country's population according to the 2011 Census. It has a significant presence in various parts of the country, with the highest concentration of Muslims in states like Jammu and Kashmir, West Bengal, Uttar Pradesh, and Bihar.

Reasons for the significant following of Islam in India:

1. Historical Influence:
- Islam was introduced to the Indian subcontinent during the 7th century by Arab traders and later by Muslim invaders such as the Ghaznavids, the Delhi Sultanate, and the Mughals.
- The long period of Muslim rule, especially under the Mughal dynasty, had a profound impact on the culture, architecture, and language of the region, which still persists today.
- Many prominent historical figures in Indian history, such as Akbar the Great and Shah Jahan, were Muslims, further contributing to the religion's influence.

2. Sufi Tradition:
- Sufism, a mystical branch of Islam, played a crucial role in spreading the religion in India.
- Sufi saints like Moinuddin Chishti, Nizamuddin Auliya, and Amir Khusro preached a message of love, peace, and harmony, attracting a large number of followers from diverse backgrounds.
- The Sufi tradition emphasized spiritual experiences and devotion, which resonated with the Indian population and facilitated the acceptance and growth of Islam.

3. Conversion and Migration:
- Over the centuries, there have been instances of conversion to Islam in India, both through peaceful means and forced conversions during periods of political instability.
- Additionally, migrations of Muslims from neighboring regions, such as present-day Bangladesh and Pakistan, have also contributed to the growth of the Muslim population in India.

4. Modern-Day Factors:
- The high birth rate among the Muslim community compared to other religious groups has also contributed to the increase in followers.
- Furthermore, factors such as education, socio-economic development, and political representation have played a role in shaping the religious landscape of the country.

In conclusion, Islam has a significant number of followers in India due to historical, cultural, and socio-economic factors. The religion's centuries-long presence, the influence of Sufism, conversions, migrations, and demographic factors have all contributed to its growth and prominence in the country.

After Hinduism, Islam has the maximum followers in India.