India's success in administering 100 crore doses of anti-Covid vaccines has generated a strong sense of optimism in all sections with experts upbeat about India's economy even as it was necessary to remember that having a strong "kavach (armour)" did not mean that people should let down their guard, Prime Minister Narendra Modi said on Friday.India's success in administering 100 crore doses of anti-Covid vaccines has generated a strong sense of optimism in all sections with experts upbeat about India's economy even as it was necessary to remember that having a strong "kavach (armour)" did not mean that people should let down their guard, Prime Minister Narendra Modi said on Friday.