We had no clue this was happening in India. We were suspicious ever since we read the illuminating study on the deadly octane enhancer, MMT (Methylcyclopentadienyl manganese tricarbonyl) from the International Council on Clean Transportation (ICCT). Scary. Manganese particles from MMT burning as a petrol additive, is a potent neurotoxin that damages the brain when inhaled. Manganese deposit fouls up vehicle components and emission control systems. As an octane booster, MMT is expected to save fuel. But in reality, as evidence shows, it barely makes any difference.