<br/>Petrol prices will go up by 50 paise a litre from midnight tonight in 13 big cities, including Delhi and Mumbai, where cleaner Euro-IV grade fuel will be supplied from tomorrow. <br/><br/>Petrol price in Delhi will go up by 50 paise per litre to 47 rupees and 93 paisa and diesel by 26 paise to 38 rupees and 10 paise a litre on account of supply of cleaner Euro-IV fuel. AIR correspondent reports, thirteen big cities, including Delhi, Mumbai, Kolkata, Chennai, Hyderabad, Bangalore, Lucknow, Kanpur, Agra, Surat, Ahmedabad, Pune and Sholapur will move from Euro-III grade fuel to Euro-IV from tomorrow. Rates will vary from city to city depending upon local taxes.