Deputy Chief Minister Manish Sisodia was attacked with ink outside Lieutenant Governor Najeeb Jung's residence here on Monday.
The attacker, Brajesh Shukla, belongs to a small NGO based in west Delhi.
Shukla claimed he was "angered" by the Deputy Chief Minister's "visuals of enjoying Finland" as the Capital reeled under the dengue and chikungunya crisis.
Mr. Sisodia, who returned to the Capital from Finland where he was on an official tour to assess and assimilate that country's education system, was speaking to the media when he was attacked.
"People from the Aam Aadmi Party are trying their best to control the crisis in Delhi while people from the Bharatiya Janata Party and the Congress are concentrating on ink," a visibly shaken Mr. Sisodia told reporters as the police overpowered and detained the accused.
Deputy Commissioner of Police (North) Madhur Verma said Shukla was detained from the spot.
Shukla, a resident of Karawal Nagar in west Delhi, yelled that he was an Aam Aadmi (common citizen) of the Capital and was angry at Mr. Sisodia's "trip abroad when Delhi needed him" before throwing ink at him.
"He is being taken to the Civil Lines police station. We will question him further to ascertain what his motive was and which group he belongs to," said Mr. Verma.
The Deputy Chief Minister had been summoned to the Capital urgently in view of the vector-borne crisis here by Mr. Jung last week.
