JOIN USThe samples were collected in the past one week, according to the official of the National Institute of Communicable Disease (NICD).
"All the suspected influenza samples available with us have tested negative for flu and now we don't have any sample. India is free from swine flu infection," the official said.
The NICD has tested 20 samples of passengers who came from countries reporting influenza A (H1N1) and reported flu symptoms.
The last batch to be cleared by the NICD included five suspects - two in Bangalore, two in Kochi and one in Delhi - who were kept under observations in government hospitals.
India has intensified measures to tackle swine flu by strengthening surveillance at road, sea and airports.
"Every day we have been screening 35,000 to 40,000 passengers at airports. (There are) 172 doctors and 83 paramedics deployed to man 68 counters at the airports," joint secretary in the health ministry Vineet Chawdhry said.
According to WHO, 21 countries have reported 1,490 cases of the influenza.