Delhi, Mumbai, Kolkata rank among world's 20 most populated cities. Their populations are...

1. Delhi - New Delhi
- Population: 33,807,403
- Change (2023-24): 2.34%
- Global Rank: 2

2. Mumbai - Maharashtra
- Population: 21,673,149
- Change (2023-24): 1.50%
- Global Rank: 9

3. Kolkata - West Bengal
- Population: 15,570,786
- Change (2023-24): 1.08%
- Global Rank: 18

4. Bengaluru - Karnataka
- Population: 14,008,262
- Change (2023-24): 0.97%
- Global Rank: 23

5. Chennai - Tamil Nadu
- Population: 12,053,697
- Change (2023-24): 0.83%
- Global Rank: 28

6. Hyderabad - Telangana
- Population: 11,068,877
- Change (2023-24): 0.76%
- Global Rank: 34

7. Ahmedabad - Gujarat
- Population: 8,854,444
- Change (2023-24): 0.61%
- Global Rank: 45

8. Surat - Gujarat
- Population: 8,330,528
- Change (2023-24): 0.57%
- Global Rank: 50

9. Pune - Maharashtra
- Population: 7,345,848
- Change (2023-24): 0.51%
- Global Rank: 58

10. Jaipur - Rajasthan
- Population: 4,308,510
- Change (2023-24): 0.23%
- Global Rank: 112

Delhi, with its population (33.8 million) surpassing those of entire nations like Malaysia, faces severe challenges in infrastructure, housing, and public services. Mumbai, too, with its 21.7 million residents, grapples with issues from overcrowded localities to inadequate sanitation. Kolkata, with 15.6 million people, makes it to the top 20 (rank 18). Tokyo tops the global list.

World Population Day, observed on July 11th, underscores the pressing issues tied to the world's swelling population. The global population, which took millennia to reach 1 billion, skyrocketed to 7 billion in just 200 years. Projections indicate this number could soar to 10.9 billion by 2100.