Complex sentence: Swami Chinmayananda started the tradition of "Jnana Yagnas", in an effort to spread the message of the Geeta and the Upanishads, thus the first such "Geeta Gyana Yagna" was held in Pune between December 31,1951 and April 1952.
Split into simpler sentences: Swami Chinmayananda started the tradition of "Jnana Yagnas", in an effort to spread the message of the Gita and the Upanishads. Thus the first such "Gita Gyana Yagna" was held in Pune between December 31,1951 and April 1952.