Content pdfs from - 

1. Wikipedia

https://era-india.org/project/aravali-biodiversity-park/

https://www.hindustantimes.com/cities/gurugram-news/aravalli-biodiversity-park-in-gurugram-declared-as-india-s-first-oecm-site-101643834401345.html

https://iamgurgaon.org/  

2. World Health Organization (WHO)

3. Britannica

4. The Tribune

5. The Times of India

6. Dainik Jagran.