What do you mean by sex ratio? Why is it important to know about it? What is meant by unfavourable sex ratio?

(i) Sex ratio is defined as the number of females per $1000$ males in the population.
(ii) This information is an important social indicator to measure the extent of equality between males and females in a society at a given time.
(iii) The sex ratio in the country has always remained unfavourable to females. It means that the number of females per $1000$ males has always remained low in our country. This is clear from the following table:
India: Sex Ratio $1951-2001$

Census Years	Sex Ratio (Females per $1000$ males)
$1951$	$946$
$1961$	$941$
$1971$	$930$
$1981$	$934$
$1991$	$929$
$2001$	$933$