Dr. Ruchir Tandon, a senior consultant in medical oncology at ShardaCare-Healthcity, highlights that 40% of all cancers are preventable through lifestyle changes. He identifies smoking as the leading preventable cause, responsible for nearly 30% of cancer deaths, and warns that passive smoking can increase lung cancer risk by up to 30% for non-smokers. Obesity follows as the second major risk factor, linked to at least 13 types of cancer. Regular exercise, such as 150 minutes of moderate activity per week, can reduce the risk of several cancers by 10 to 20%. Diet also plays a crucial role; for instance, just 50 grams of processed meat daily can raise colorectal cancer risk by 18%. Additionally, Dr. Tandon points out lesser-known risks, such as radon gas exposure and the dangers of night-shift work, which disrupt melatonin production and are classified as probable carcinogens. He encourages individuals to make small, sustainable changes in their habits, as these can significantly lower cancer risk over time.