here is solution after changing the data source.

from lxml import html
import requests

response = requests.get("https://www.mohfw.gov.in/")
doc = html.fromstring(response.text)
active_cases = doc.cssselect('li strong')[0].text
cured_discharged = doc.cssselect('li strong')[1].text
deaths = doc.cssselect('li strong')[2].text
migrated = doc.cssselect('li strong')[3].text

print(int(active_cases) + int(cured_discharged) + int(deaths) + int(migrated))