[jjotto]

https://www.chabad.org/holidays/purim/article_cdo/aid/645278/jewish/Shushan-Purim.htm

Shushan Purim
Why Jerusalem celebrates a day later
By Naftali Silberberg

The battles fought between the Jews and their enemies throughout the Persian empire took place on 13 Adar. Around the world, the Jews rested and celebrated on the following day—14 Adar.

In the capital city of Shushan, however, where there were a greater number of Jew-haters, the fighting continued for two days, 13 and 14 Adar. The victory celebrations in Shushan were thus held on the 15th...

[Wuli]

Thanks so much.