**Core Concept**
The National Leprosy Eradication Programme (NLEP) is a government-led initiative aimed at eliminating leprosy as a public health problem in India. Leprosy, also known as Hansen's disease, is a chronic bacterial infection caused by *Mycobacterium leprae* that primarily affects the skin, peripheral nerves, and mucous membranes.

**Why the Correct Answer is Right**
NLEP was launched in 1983 with the goal of reducing the prevalence of leprosy in India to less than 1 case per 10,000 population. The programme involved a multi-faceted approach, including early case detection, multidrug therapy, and social rehabilitation of leprosy-affected individuals. This comprehensive strategy has contributed significantly to the decline in leprosy cases in India.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the National Leprosy Eradication Programme was not launched in the 1970s, which was a period of significant leprosy prevalence in India.
**Option B:** This option is incorrect because the programme was not initiated in the 1960s, which was a time of limited public health infrastructure in India.
**Option C:** This option is incorrect because the programme was not launched in the 1990s, which was a period of transition towards community-based health care in India.

**Clinical Pearl / High-Yield Fact**
The NLEP's emphasis on early case detection and multidrug therapy has been instrumental in reducing the prevalence of leprosy in India. It is essential for healthcare professionals to recognize the signs and symptoms of leprosy, such as skin lesions, nerve damage, and eye problems, to ensure timely diagnosis and treatment.

**Correct Answer: C. 1983**