26th January 1950 was the day when constitution of India was adapted which was passed by constituent assembly of India on 26th November 1949. The constitution was drafted by team of Dr. B. R. Ambedkar. This day is celebrated in India as republic day and today; India is celebrating 65th republic day.
Every year, 26th January is celebrated by flag hoisting ceremony honorable president of India followed by republic day parade at New Delhi. Whole country is celebrating this day by remembering soldiers and people who fought for freedom of nation.
Flag hoisting ceremony and republic day parade can be watch life by visiting this government of India official website for republic day celebration information: http://republicday.nic.in/
As you can see in given image, soldiers from different regiments participate in republic day parade.
image credit: http://pib.nic.in/release/phsmall.asp?phid=44956