Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 18: The Advent of Rāma, Lakṣmaṇa, Bharata and Śatrughna
Text 1.18.18

उत्सवश्च महानासीदयोध्यायां जनाकुलः॥

utsavaś ca mahān āsīd ayodhyāyāṁ janākulaḥ

utsavaḥ ca = festival; mahān = great; āsīt = took place; ayodhyāyām = in Ayodhyā; jana-ākulaḥ = with excited people.

A great festival with excited people took place in Ayodhyā.

This is a description of the birth celebration (jāta-karma) festival on that occasion. “In Ayodhyā” indicates that this festival took place in every house [all over Ayodhyā].