77th Republic Day Parade: What is S-400? How did Indian military deploy it against Pakistan during Operation Sindoor?

India is celebrating its 77th Republic Day on 26 January 2026. On this day in 1950, the Indian Constitution came into effect, making India a sovereign democratic republic.

The formal state ceremony starts with Prime Minister Narendra Modi visiting the National War Memorial. He will pay tribute to fallen soldiers by laying a wreath and observing a two-minute silence.

President Droupadi Murmu will arrive at Kartavya Path with Chief Guests, Antonio Costa and Ursula von der Leyen, in the traditional ceremonial buggy.

She will unfurl the National Flag, followed by the National Anthem and a 21-gun salute using indigenous 105mm Light Field Guns. The main parade will then begin at 10:30 AM.

During the Republic Day 2026 parade, India will display its military power. Key weapon systems that the Indian military deployed during Operation Sindoor were part of the parade at the 77th Republic Day celebrations. One of the key showcases is the S-400.

What is S-400?

The S-400 air defence system will be displayed to the public for the first time at the Republic Day 2026 parade. It will appear in the Department of Military Affairs tableau. The system played a key role during the India-Pakistan military conflict in May 2025.

During Operation Sindoor, the S-400 successfully intercepted aerial threats. After the Operation Sindoor, Air Chief Marshal Amar Preet Singh confirmed that five Pakistani fighter jets had been shot down by India with the help of the S-400.

Republic Day 2026 celebrations

India marked the start of Republic Day 2026 celebrations with tight security across the country. Security was stepped up in Delhi-NCR and along the Line of Control (LoC).

To help people reach parade venues on time, Delhi Metro services started as early as 3 AM. Across India, schools, government offices and residential societies held flag-hoisting ceremonies between 7:30 AM and 9 AM.

Republic Day 2026 messages

Political leaders also shared Republic Day messages. Prime Minister Narendra Modi, Union Ministers and several Chief Ministers greeted citizens on social media.

“Best wishes on Republic Day. May this occasion add renewed energy and enthusiasm in our collective resolve to build a Viksit Bharat,” PM Modi wrote on Twitter (now X).

International leaders also joined in, with greetings from the United States and China early in the day.

“On behalf of the American people, I congratulate the people of India on Republic Day. Through cooperation in defense, energy, critical minerals, emerging technologies, and the Quad, the U.S.-India partnership delivers real results for both nations and the Indo-Pacific,” US Secretary of State Marco Rubio stated.

Chinese President Xi Jinping sent a message to President Droupadi Murmu. He called New Delhi and Beijing “good neighbours, friends and partners”.

“Heartfelt Republic Day wishes to all my fellow citizens. Our Constitution is the greatest weapon for every Indian - it is our voice, the protective shield for our rights,” Rahul Gandhi, Leader of Opposition in Lok Sabha, wrote on social media.

West Bengal Chief Minister Mamata Banerjee wrote, “I am reminded today of the old saying: eternal vigilance is the price of liberty. I urge everyone today to exercise this vigil. Our republic and our Constitution today demand our collective vigilance.”

The interest in ‘Republic Day’ on Google soared from 25 January to 26 January: