Section 19 of Evidence Act "Admissions by persons whose position must be proved as against party to suit"
Statements made by persons whose position or liability it is necessary to prove as against any party to the suit are admissions, if such statements would be relevant as against such persons in relation to such position or liability in a suit brought by or against them, and if they are made whilst the person making them occupies such position or is subject to such liability.
Illustration
A undertakes to collect rents for B.
B sues A for not collecting rent due from C to B.
A denies that rent was due from C to B.
A statement by C that he owned B rent is an admission, and
is a relevant fact as against A, if A denies that C did owe
rent to B.
Section 20 of Evidence Act "Admissions by persons expressly referred to by party to suit"
Statements made by persons to whom party to the suit has
expressly referred for information in reference to a matter
in dispute are admissions.
Illustration
The question is, whether a horse sold by A to B is sound.
A says to B- " Go and ask C, knows all about it" C's
statement is an admission.
What is when facts not otherwise relevant become relevant Section 11 of Indian Evidence Act 1872
What is Admission- by party to proceeding or his agent Section 18 of Indian Evidence Act 1872