A purported video of his speech, made during campaigning in the Dabhoi constituency, had surfaced amid the controversy over veteran Congress leader Mani Shankar Aiyar's "neech" slur on Prime Minister Narendra Modi.
In the purported video, Mr Mehta is heard saying, "If any 'topi, daadhiwala' (anybody wearing a cap and sporting beard) is sitting here (in the crowd), pardon me, but there is a need to reduce their population. Many leaders asked me not to say this, as it may go against me, but if 90 per cent of people are supporting me, why should I stop speaking about the 10 per cent people?"
He further said, "I will not allow this town to become another Dubai and like my opposition candidate I will not pay even a single penny to Madrasas or mosque, I assure you".
Mr Mehta, 45, joined the BJP five years ago. Earlier he was part of the Nationalist Congress Party and had been a corporator from Vadodara.
Mr Mehta's opponent, Congress's Siddharth Patel said, "This shows their mentality... they want to polarise the elections, but people have seen through their dirty game".
After the video was aired by local television channels, Ahmedabad-based social worker Nishant Varma filed a complaint with the Election Commission. "He (Sotta) is clearly heard saying that Muslim population must be reduced in the area, and that Muslims will face 'eent ka jawab pathhar se'... this is unacceptable," Mr Varma said in his complaint, reported news agency Press Trust of India.
The BJP, which has been in power in Gujarat for 22 straight years, is trying to make a comeback in an election that's seen as a referendum on the Central government's flagship Goods and Services Tax or GST, which was rolled out in July.
The Congress claims GST and before that, the notes ban, has hugely inconvenienced small traders, who comprise a huge section of the population. In his rallies, Rahul Gandhi, who is set to be the next Congress chief, has criticized both in scathing terms. His party has accused the BJP of playing the communal card in Gujarat to hang onto power.