As on 24 dec is a settlement holiday

As on 24 dec is a settlement holiday. I brought 20 shares of sbi, Bse. On 22 dec and on 23 dec i sold 20 shares. Now i have 100 shares of sbi, Nse. Now what is the effects of settlement holiday on my trade and in case there is short delivery what happens.

For shares bought on 22 dec will get credited in to your demat on(t+2) dec 28. and will be debited on (t+2)dec 29 as you sold on dec 23.

Assuming from your question that you already have shares of sbi in your demat bought from Nse then there is no risk of short delivery.

please refer to this link to know more about settlement holiday:-