The move is seen as a shot in the arm for the BJP as elections to the three municipal corporations of Delhi (MCDs) are scheduled to be held on April 23.
Ved Parkash, who represented Bawana in the assembly, alleged that the MLAs who talk of development are "suppressed" by the party's top leadership.
He joined the BJP at its Delhi unit office in the presence of Delhi BJP president Manoj Tiwari and state party incharge Shyam Jaju. Later, accompanied by Leader of Opposition Vijender Gupta, he submitted his resignation at the Assembly Speaker's office.
He said Chief Minister Arvind Kejriwal is not "concerned" about what is happening at ground level and instead, he only focuses on how to "defame" Prime Minister Narendra Modi and his government.
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He said that the AAP government is "being run through laptop" and that there is no connect with the ground reality.
"I had joined the AAP with a hope that there will be some change, but I am disillusioned...I have neither quit under duress nor will I take any post in the BJP and will abide by the decisions taken by the party leadership.
Delhi BJP chief Tiwari said that the people of Delhi have now understood how they were "cheated" by the Aam Aadmi Party.
"Corruption has not been brought down in Delhi. There is corruption in every department in government. People are unhappy with the government's performance. Every person is feeling cheated.
"They (AAP) have failed to deliver on promises made in the run-up to assembly elections. What is about promises like Wi-Fi, CCTVs and women safety," he said.
There are also four rebel MLAs -- Devinder Sehrawat, Pankaj Pushkar and former ministers Sandeep Kumar and Asim Ahmed Khan.
The political development comes days after BJP President Amit Shah gave a call to "uproot" the Aam Aadmi Party from Delhi at the party's booth in-charge convention here.
Reacting to the resignation, a senior AAP leader said, "The party ticket for the MCD polls were given after consulting Ved Parkash. There could be a disagreement over one seat, but we did not expect him to quit."
He alleged that AAP ministers do not pick up calls of legislators, adding that no work has been done by the government in his constituency.
He also took a dig at Deputy Chief Minister Manish Sisodia's ambitious project to send the government's principals abroad for training skills.
"In my constituency, there is a shortage of 30 per cent of teachers in a government school and they (AAP) talk of sending teachers abroad. Also, SC/ST fund has been lying unspent," he said.
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