Instead of Nachiyar Tirumozhi parayana day, why is the nURu thadA Utsavam celebrated at many temples on ‘kUDArai veLLUm’ pasuram day? Also, why is sweet Pongal (sarkkarai Pongal) offered instead of akkAravaDisil and butter as mentioned in the pasuram?

Nachiyar desired to offer “nURu thadA akkAravaDisil sonnEn”; even in the Kudaravalli pasuram it is mentioned “…pAlsORu mUDa ney peidu muzhangai vazhi vAra kUDiyirundu kuLirndu..”, akkAravaDisil is offered. So, we do as per the wish of Nachiyar. It is believed that Sri Bhasyakarar offered at Tirumalirinjolai – hence we have the practice of offering this as form of remembrance.
akkAravaDisil and sweet Pongal are almost the same and differ only in the way they are prepared. ‘akkAram’ is sugar or jaggery derived from sugar cane. In the olden days, jaggery was termed sugar (sarkkarai); ‘aDisil’ is cooked rice. So rice prepared by mixing with jaggery is ‘akkAravaDisil’. This is also the sweet Pongal. Both are same.