The Central Bureau of Investigation (CBI) on Wednesday raided over 25 residences and offices of officials of the Municipal Corporation of Delhi (MCD).
Senior officials said the CBI had recently registered five cases of corruption against MCD officials and the raids were carried out to gather more evidence.
"The MCD officials have been charged of colluding with private persons and builders to carry out unauthorised constructions and encroachments," said a senior CBI official.
He added that offices and residences of the officials of the rank of deputy commissioner, executive engineers, assistant engineers and junior engineers were raided.
Some of these houses were in upmarket areas like Vasant Kunj, Rajouri Garden, Civil Lines and Shakti Nagar.