The construction of a sixth floor is unauthorised, and as such, it
cannot be lawfully sold or purchased. The agreement for the sale
of an unauthorised construction is void under Section 23 of the
Indian Contract Act as its consideration is illegal.
11.14 Once it is established that the consideration was illegal,
Section 43 of the Negotiable Instruments Act would also come
into play as per W.S. Sethu Narayana Babu (supra) and the
cheque Ex PW1/E would create no obligation on the defendant to
pay.