The Radhapuram constituency was not contested by the DMK in the 2011 elections because they entered into an alliance with the INC.[6] In the 2016 elections, Appavu again contested the seat as a DMK candidate. In a surprise result, he lost by 49 votes to I. S. Inbadurai of the All India Anna Dravida Munnetra Kazhagam (AIADMK).[7] This was the narrowest losing margin in the state[8] and he appealed against the outcome, arguing amongst other things that the Returning Officer had improperly rejected some postal votes.[9] He had staged a protest regarding the matter at the time of the count, which led to him being evicted from the building.[10]
He contested 2021 assembly election from Radhapuram constituency as a DMK candidate and won with a margin of about 5000 votes.[11]
In May 2021, he was elected unopposed as the speaker of the 16th Tamil Nadu Legislative Assembly.[12]
Campaigning
Appavu's campaigning for farmers' rights has led him to file Public Interest Litigation papers on several occasions.[9] In 2013, he spoke in court of the need to impose minimum price controls on agricultural produce in order to reduce the alleged incidence of suicide among farmers and to prevent profiteering by middlemen. He also wanted an improved agricultural insurance scheme to ward against the effects of crop losses that occurred as a consequence of natural events.[13]
Appavu has also been associated with matters relating to water supplies and was responsible for the introduction of drinking water schemes that use the Ponnankurichi and Tamirabarani rivers.[2] In 2017, he won an order at the Madras High Court that the Government of Tamil Nadu should comply with the court's instructions of 2002 to investigate the relationship between incidences of water scarcity and the practice of river sand quarrying for construction purposes.[14] At the same time, he was campaigning against water extraction from the Tamirabarani river by businesses associated with PepsiCo and Coca-Cola. He argued that the government was preferring the needs of the businesses over those of the population in area where water was scarce. He said that while other businesses that took more water were justified in doing so, the soft drinks businesses were exploitative because they were "commodifying water by fetching it for a minuscule price and selling it later for an astronomically higher price".[15]
There was some controversy in 2009 when there was an attempt to name a bus-stand in Radhapuram after the parents of DMK leader, Karunanidhi, and to erect statues commemorating them. The AIADMK claimed that the DMK-led government was facilitating the idea but the government said that the project was led by Appavu and 90 per cent funded by him.[16] After much back-and-forth disputation, the stand was eventually named in honour of K. Kamaraj in 2010.[17]