A study conducted by Central Pollution Control Board has said that 85 per cent of big industrial clusters in India are health hazards. It said that air, water and land pollution levels are not fit for human habitants in these clusters.The study, Comprehensive environmental assessment of industrial clusters, undertaken by IIT Delhi and the CPCB, found that the environmental pollution levels in 10 major industrial hubs had reached a very alarmingly high level. This list includes Ankleshwar and Vapi in Gujarat , Ghaziabad and Singrauli in Uttar Pradesh, Korba (Chhattisgarh), Chandrapur (Maharashtra), Ludhiana (Punjab), Vellore (Tamil Nadu), Bhiwadi (Rajasthan) and Angul Talcher (Orissa). The study said that the problem in most critically polluted areas is highly serious, as the effluent from industries is discharged at night. Villages in polluted areas of Vapi and Ankleshwar in Gujarat have not seen clean drinking water since a long time and water in Vapi Town is not potable. High degree of asthma cases and irritation, particularly in eyes are prevalent among people.