Explanation:

These come under the Ministry of Home Affairs.

1. Assam Rifles (AR)
Established in 1835, Assam Rifles is the oldest of all paramilitary forces. There are currently 46 battalions of AR under the Ministry of Home Affairs.
2. Border Security Force (BSF)
BSF came into being in the wake of the 1965 Indo-Pakistan war, to ensure the security of the borders of India. It is headed by an officer from the Indian Police Service just like all other paramilitary forces except Assam Rifles.
3. Central Industrial Security Force (CISF)
CISF's job is provide security to Public Sector Undertakings (PSUs). Currently they provide security cover to 300 industrial units.
4. Central Reserve Police Force (CRPF)
The CRPF looks after the internal security of every part of India.
5. Indo-Tibetan Border Police (ITBP)
The ITBP was established after the 1962 Indo-China war, under the CRPF Act. It vigils the northern borders, detects and prevents every border violations and helps the locals feel secure.
The force also keeps a check on illegal immigration and trans-border smuggling. They guard the Indo-Tiber border and the mountainous regions of the Indo-China border.
The ITBP is also trained in disaster management and have been deployed in UN peacekeeping missions in Bosnia and Herzegovina, Kosovo, Sierra Leone, Haiti, Western Sahara, Sudan, and Afghanistan.
6. National Security Guard (NSG)
The formation of NSG was a consequence of the assassination of Indira Gandhi and Operation Blue Star. It was raised to combat terrorist activities and to ensure the states do not witness any internal disturbances.
They are often referred as Black Cats because of their uniform which consists of a black dress and black cat insignia.
7. Sashastra Seema Bal (SSB)
Established in 1963, the SSB guard the Indo-Nepal and Indo-Bhutan borders.