VALENCIA, Spain - Williams driver Pastor Maldonado was handed a 20-second penalty by race stewards for colliding with McLaren's Lewis Hamilton during the European Grand Prix.Maldonado was battling with Hamilton for third place before the two collided towards the end of the race, sending the McLaren driver into the barriers. The 2008 champion was forced to retire while Maldonado finished in sixth.After the race the Maldonado claimed that Hamilton, who was struggling for grip at that point, had been driving too aggressively.STEWARDS KEPT BUSYMaldonado said: "I don't know why he drove like that. He was struggling too much with the tyres. He was completely lost and at that moment I was getting very good pace. He tried a very aggressive move on me."Maldonado's penalty moved him down to 12th place.Toro Rosso driver Jean-Eric Vergne and Sauber's Kamui Kobayashi were also each handed grid penalties for the upcoming 2012 British GP after causing other collisions during the race. Vergne was given a R264 000 fine and a 10-place grid penalty for crashing into Caterham driver Heikki Kovalainen and Kobayashi will drop five places for his collision with Ferrari's Felipe Massa.Michael Schumacher was also under investigation for using his car's drag reduction system in a yellow flag zone.However, the Mercedes driver was not penalised and will retain his third-placed finish.