5 rupee with wave design, 2007A number of such 5 rupee coins were in circulation, which were actually fake. The only visible pointer of this coin being a fake is the fuzziness of the design. If you want to know more, then I can tell you that this coin is made of iron, and hence magnetic. If you leave such a coin in moist air for sufficient period of time, then it would also rust. In contrast, the genuine 5 rupee with same design was made of stainless steel.
I also came across similar 5 rupee coins which were made from the commemorative coins of SBI(state bank of India) which were also in circulation.
Indira Gandhi 1 rupee
Indira Gandhi 1 rupee with mala
The Indira Gandhi 1 rupeee is a bad forgery and I believe that even a layman should be able to tell this is a fake. Any Indira Gandhi coin was never minted in the 1 rupee denomination, and also no Indira Gandhi coin showing the front face has been minted. I have no idea how someone got the idea of putting a mala(necklace) in Indira Gandhi's neck.
BR Ambedkar 2 rupee
This BR Ambedkar 2 rupee is perhaps the best fake in republic India that I have come across so far. The Ambedkar 2 rupee was never minted by the government, only the one rupee was. The obverse with the denomination looks perfectly fine, though an experienced numismatist knows that the style of the '2' in the 2 rupee coins has been changing ever since its inception. If you have knowledge you would know that the '2' in the 1990 2 rupee coin differs from the '2' in the 2000 two rupee coin(Ambedkar centenary was in 1990). The '2' design on this coin is the same as the design on the 2 rupee coins of 2000-2004, meaning that this coin was made some 5-6 years back, and not in 1990. Now moving on to the reverse, we see the Ambedkar figure. The coin is shining but the figure is a little worn out. The shine tells that the coin is freshly minted. But this contradicts the story told by the wear and tear, which suggests that the die used for this forgery was made from a worn out coin. The pronounced features are also pointers of a forgery.