How can we put 30 balls in 7 pockets in odd numbers? No even numbers only odd numbers?

Factors of 30 are:
1 - 30
2 - 15
3 - 10
5 - 6

You put 5 balls in each of 6 glasses and 0 in the last glass. You can only remove even numbers to transfer to the last glass, and no combination of even numbers makes an odd number, so there is no other possible way to do it. So your answer is 5 balls in each of six glasses and 0 in the last. It's a ruse: 0 is neither odd nor even.