PM Modi remembered Queen Elizabeth II as a "stalwart of our times".
As India observes one-day state mourning as a mark of respect to Britain's Queen Elizabeth II, who died on September 8, the national flags at all government buildings including Red Fort and Rashtrapati Bhavan fly at half-mast on Sunday.
Queen Elizabeth II, United Kingdom of Great Britain and Northern Ireland breathed her last in Scotland.
"As a mark of respect to the departed dignitary, the Government of India has decided that there will be one day of State Mourning on September 11th throughout India," reads a statement from the Ministry of Home Affairs.
On the day of mourning, the National Flag will be flown at half-mast throughout India on all buildings where the National Flag is flown regularly and there will be no official entertainment on the day.
People in India also paid respects to Queen Elizabeth II who became the UK's longest-serving monarch in 2015, when she surpassed the record of Queen Victoria, who had ruled from 1837 to 1901.
"We came for a visit here. I like Queen very much but it was unfortunate that we won't be able to see her anymore. We respect the Royal Family and our prayers are with the family in this difficult time. We congratulate and extend best wishes to the new King Charles III," said a woman from Kerala, who came to visit Delhi.
"We want to give respect to the Queen because she has done many things for India. India and UK has a strong relationship for many years and to continue this we should give respect to the Queen," said a local resident.
"We all should mourn the demise of Queen Elizabeth because she has contributed in the formation of our Constitution. We support the government decision to observe state mourning for Queen," said another resident.
Another person, who was near the Parliament, hailed the Modi government for observing one-day state mourning.
"This is the great decision taken by the Modi government, after all, she was the head of the Commonwealth nations. The entire world saw her as the mother patriarch," he said.
Condolences poured in from around the world following the demise of the 96-year-old monarch.
Prime Minister Narendra Modi remembered her as a "stalwart of our times", saying she "provided inspiring leadership to her nation and people" and "personified dignity and decency in public life".
Buckingham palace announced she died at Balmoral Castle where members of the royal family had rushed to her side after her health took a turn for the worse.
The Queen had been suffering from what Buckingham Palace called "episodic mobility problems" since the end of last year. After her coffin is brought back to London, the Queen will lie in state in Westminster Hall for about four days before her funeral.
A period of royal mourning, following the death of Queen Elizabeth II, will be observed from now until seven days after the Queen's funeral, the date of which will be confirmed by the Royal Family in due course.
Royal mourning will be observed by members of the Royal Family, Royal Household staff and representatives of the Royal Household on official duties, together with troops committed to ceremonial duties, the Royal Family said in a statement.
Flags at Royal residences were half-masted on Thursday and will remain half-masted until 0800 hrs on the morning after the final day of royal mourning. The half-masting of flags at Royal residences does not apply to the Royal Standard and the Royal Standard in Scotland when the King is in residence, as they are always flown at full mast.
As the longest-serving monarch of the UK, Queen Elizabeth II died on Thursday her seven-decade-long reign came to an end. It has triggered questions regarding further proceedings and the transition of powers. According to a professor of British and Commonwealth history at the University of London, Philip Murphy, the Whitehall started the planning process about what would happen when the Queen dies from the time she became one, New York Times reported.
Lastly, Charles will take the Coronation Oath following which a proclamation will be read, declaring the reign of the new king, the New York Times reported. The UK authorities had devised Operation London Bridge to manage events during the first 10 days between the Queen's death and the funeral. They had thought of Operation Unicorn in case the queen died in Scotland.
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