India is celebrated the milestone of administering 1 billion COVID-19 vaccine doses with a song and dance.The government on Thursday (October 21) promoted the achievement with musical and other programs across the country.And special illuminations of national monuments - even as a recent drop in inoculations worries healthcare providers.Prime Minister Narendra Modi marked the occasion by meeting staff at a hospital in New Delhi."October 21, 2021, has been scripted in history as India has crossed the 100 crore (one billion) mark of administering COVID-19 vaccine doses. Now, the country has a strong shield of 100 crore vaccine doses to fight the biggest pandemic in the last 100 years."Rajesh Dere is a health care worker at a vaccination center."It's like a festival for us as 100 crore (one billion) doses have been administered and with the efforts of everyone the pandemic has been controlled in Maharashtra and the entire country."The World Health Organization (WHO), which relies heavily on India for supplies to its global vaccine-sharing platform COVAX, congratulated the country for reaching the landmark.After a slow start in January, India's immunization campaign has covered three-quarters of its 944 million adults with at least one dose but only 31% have received both doses.Nearly 90% of the vaccines administered have come from the Serum Institute of India.It produces a licensed version of the AstraZeneca drug..The SII has more than tripled its capacity since April and can now produce 220 million vaccine doses a month.Ministry officials are urging people to get vaccinated fast, especially as the ongoing festival season of family gatherings and mass shopping raise the risk of a new wave of infections.