فَإِنْ حَدَثَ عُذْرٌ مَنَعَ النَّاسَ مِنَ الصَّلَاةِ يَوْمَ الْأَضْحَى: صَلَّاهَا مِنَ الْغَدِ وَبَعْدَ الْغَدِ، وَلَا يُصَلِّيهَا بَعْدَ ذَلِكَ.
Translation: If a valid impediment prevents the people on Adha day, the prayer may be performed on either of the next two days, but not thereafter.
The normal Adha date is 10 Dhu al-Hijjah. Under this ruling, a communal impediment permits holding it on the 11th or 12th, but no later; Fitr has a narrower extension.