not a investment post but just something I noticed staying in the UK. More than 60% of all passenger cars here are diesel engined, especially newer cars (2001 and newer).
Diesel has many pros over petrol especially in a metro driving setting; it has more low end torque (more power at lower revs) and is much much more economical than petrol (some cars like the citroen c3 diesel can get up to 30-35km/l on expressway driving). Not to mention cheaper than petrol (in singapore at least. it's more expensive in the UK). what puzzles me is why the government imposes a diesel car tax and the car makers arent keen on bringing in diesel models. the modern diesel car has much less CO2 and particulate emission and may even be cleaner than petrol cars (except NOx emissions).