Section 190
When agent cannot delegate
Chapter 11: Agency
An agent cannot lawfully employ another to perform acts which he has expressly or impliedly undertaken to perform personally, unless by the ordinary custom of trade a sub-agent may, or, from the nature of the agency, a sub-agent must, be employed.
The Indian Contract Act, 1872 (Act No. 9 of 1872). From the updated text on India Code, with later amendments. Being checked against the official copy; amendment notes are not shown yet.