In 2013 and 2014, a report said, around Rs 1,500 crore of fake currency was pumped into the Indian economy. A confidential government report admitted that four out of every 1,000 notes are fake. In 2010, the circulation of counterfeit currency amounted to some Rs 3,200 crore.

If that makes you wonder whether all the notes you have are genuine, the video above is the primer you needed, telling you how to tell the real apart from the fake.

Here's a compilation of how Indian currency has changed through the ages. Be forewarned, it's set to AR Rahman's rendition of Vande Mataram.