Police Commemoration Day is observed in India on:

Police Commemoration Day (Police Martyrs' Day) is observed in India every year on 21 October in memory of police personnel who have laid down their lives in the line of duty.

Why 21 October:

• On 21 October 1959, ten personnel of the Central Reserve Police Force (CRPF) were killed in an ambush by Chinese troops at Hot Springs in Ladakh, at a height of over 15,000 feet, while patrolling the India-China border.
• Several others were captured and later returned.

In January 1960, at a conference of the Inspectors General of Police of the states and Union Territories, it was decided to observe 21 October as Police Commemoration Day in honour of the martyrs of Hot Springs and all police personnel who die on duty.

Every year, a team of police personnel goes to Hot Springs to pay homage at the memorial there.

National Police Memorial:

• It was inaugurated by Prime Minister Narendra Modi on 21 October 2018 at Chanakyapuri, New Delhi.
• Its central sculpture is a 30-foot-tall, 238-tonne granite monolith representing the strength and sacrifice of police personnel.
• It includes a "Wall of Valour" with the names of over 34,000 police personnel who died on duty since independence, and a museum.

Policing in India:

• "Police" and "public order" are State subjects under the Seventh Schedule of the Constitution (List II).
• The Central Armed Police Forces (such as the CRPF, BSF, CISF, ITBP and SSB) are under the Union Ministry of Home Affairs.
• The CRPF, the oldest of these, was raised on 27 July 1939 as the Crown Representative's Police.
• The Sardar Vallabhbhai Patel National Police Academy, Hyderabad, trains IPS officers.

Other related days:

• Civil Services Day: 21 April.
• BSF Raising Day: 1 December.
• Army Day: 15 January.

Why not the other options?

• ✗21 April is Civil Services Day.
• ✗1 December is BSF Raising Day.
• ✗15 January is Army Day.