anunaasika Rule

The rules pertaining to writing the nasal consonants (anunaasika-s) in between words -

• The nasal consonant present in between the words depends solely on the alphabet that follows it.  The nasal consonant has to be one from the same varga of the consonant that follows, if it is a vargIya vyanjana (a grouped consonant).  Ex.  

1. कङ्कण (ka~nkaNa - bangle)
2. चञ्चल (cha~nchala - movable, unsteady)
3. अण्ड (aNDa - egg)
4. तन्तु (tantu - cord, thread)
5. कम्पन (kampana - trembling)

Notice how the nasal consonants (anunaasika-s) are followed by consonants of their own vargas.  It is not correct to write कन्कण, चन्चल, अंड, तंतु, कंपन, etc.