Why do we say the Mahatma Gandhi series of Banknotes has special features?

the mahatma Gandhian series of banknotes bearing the portrait of mahatma Gandhi's has several special features that make it difficult for any one to copy or counterfeit them. if you hold a bank note up to the light, you will see that it contains the mahatma Gandhi watermark, whit a light and shade effect, and multi-directional lines in the watermark wind. you will also note a security thread that appears as one continuous line. half the numeral of each denomination is printed on one side, and half on the other, though they will appear as one continuous number when held against the light. this is called see-through registration.
the ink used is optically variable,which means that it appears green when the note is held flat, but blue when it is held at an angle. the number panels are also fluorescent. the portrait of mahatma Gandhi, the reserve bank seal,the guarantee and promise clause, the Asoka pillar emblem on the left, and the reserve bank of India governor's signature are printed in intaglio or in raised print, which can be felt be by touch. this will help blind persons to identify the bank note.