Ahead of today's sole practice session, the air temperature is 28 degrees C, while the track temperature is 35 degrees. Humidity is 35% and it is extremely smoggy.

Felipe Massa led the way yesterday, with teammate Fernando Alonso third, however, the Red Bulls and McLarens were on the pace, unlike Mercedes whose two drivers were at the other end of the timesheets.

Whether Ferrari's pace is genuine remains to be seen however, there is concern at the new front wing the team is using which wobbles violently and appears to scrape the ground.

Other than a couple of engine failures, yesterday was noticeable for the amount of offs drivers were having, the greenness of the track and the excessive dust catching out almost everyone.

Lewis Hamilton and Sergio Perez were also caught out by the waved yellow flags at the end of the opening session, both drivers receiving grid penalties of three places.

The lights go green and Alguersuari, Karthikeyan, Perez, d'Ambrosio, Petrov, and Maldonado are among the first out. Hamilton and the Mercedes duo are among the early risers.

Unusually, this weekend the prime tyre is soft while the option is the hard. Also, like Monza and Montreal, there are two separate DRS zones here.

Eight minutes into the session everyone has been out for an installation lap.

Eleven minutes into the session, Schumacher is the first driver out for a second run. The German is followed by a number of other drivers including Perez, Karthikeyan and Alguersuari.

After the first round of laps, Schumacher leads the way with a 1:30.948, Alguersuari is second over 1.1s behind.

Lap after lap Schumacher improves (29.553) dispelling, to some extent, the fear that the German team is struggling here. Elsewhere, a big spin for Karthikeyan while Rosberg goes fourth (30.312).

A 29.384 sees Webber go quickest, the Australian losing time in traffic on his previous lap. As Schumacher pits there are 19 cars on track.

Webber improves with a 28.438 and Rosberg goes second (29.262) as Vettel posts 30.196 to go ninth. No times as yet from the McLaren and Ferrari duos.

Vettel takes his usual place at the top of the table with a 28.347, out-pacing his teammate by 0.091s. All running thus far on the harder tyre. It's already believed that some drivers won't run in Q3 today in order that they can start on the option tyre and therefore get them out of the way as soon as possible.

As the McLarens leave the pits, Vettel ups the ante with a 26.906, extending the gap to Webber to 1.102s.

Almost thirty minutes into the session, Schumacher is back on track, the first driver to switch to the prime (softer) rubber. Vettel improves yet again, this time posting a 26.311.

Hamilton goes eleventh and Button sixteenth as the Ferraris head down the pitlane.

On his first lap on the soft rubber Schumacher improves with a 27.296 to go second, while Button goes fourth (28.789) and Hamilton fifth (29.000).

Alonso goes fifth with 28.699 while yesterday's pace-setter, Massa, can only manage twelfth (29.556). On the back straight there are sparks coming from the front wing where it is scraping the ground. Apparently the FIA has looked at it and is satisfied that it is within the rules. Both drivers are running it but it is only really vibrating violently on the Brazilian's car.

Rosberg (softs) goes second (26.873), ahead of Schumacher, Button, Webber, Massa, Hamilton, Petrov, Alonso and Perez.

From out of nowhere, Senna produces a 27.864 to go fifth, elsewhere, Alonso runs wide in Turn 6.

Barrichello complains of "noise from the front wing" as Alonso has another close encounter with the kerbing.

Alguersuari pops up in fifth with a 27.397 as Schumacher comes out for another run on the softer rubber. Vettel still leads the way however, his time, ominously, posted on the hard rubber.