Senior officials braved scorching sun to walk or take buses to work to mark World Environment Day yesterday. Financial Secretary Donald Tsang Yam-kuen squeezed on to the 6X bus from his Shouson Hill Road home with armfuls of files - but said he did not object. Asked whether he had taken the opportunity to talk to other passengers, he said: 'I indulged myself listening to the radio.' Secretary for Justice Elsie Leung Oi-sie, who spent the night at her mother's home in Lyttleton Road, Mid-Levels, instead of her official residence in Severn Road, the Peak, took the No 23 bus to her Admiralty office. There was an awkward moment as Miss Leung boarded the bus - she confused the Octopus card machine with the coin box and the driver had to show her where to put the money. A spokeswoman for the Department of Justice said: 'It's not the case that she's never been on a bus. It's just that she's rarely used the bus since she became Secretary for Justice.' Chief Executive Tung Chee-hwa preferred to walk, setting off at 6.30am. It took him about 20 minutes from his home in Grenville House to the Central Government Offices. A Chief Executive's Office spokeswoman said Mr Tung, dressed in tracksuit and accompanied by two bodyguards, was at work before 7am. 'He will take an LPG [liquefied petroleum gas] taxi home,' she said. Chief Secretary for Administration Anson Chan Fang On-sang opted to take an LPG government car instead of her usual limousine with the 'CS' number plate from her official residence in Barker Road, the Peak, to her Central office. She said a 'very tight schedule' meant she could not take public transport. Most of the 7,000-plus government fleet is petrol-driven, with 2,000 diesel-driven. A spokeswoman said the Government planned to convert its diesel fleet to ultra-low sulphur diesel this year. But she said there was no immediate plan to change the petrol vehicles because it was not cost-effective. She said such vehicles were 'still within their working life'. Legco President Rita Fan Hsu Lai-tai took the Airport Express from Chek Lap Kok to the legislature in Central, having returned from a mainland trip with her daughter. The car park outside the Legco Building in Jackson Road was unusually empty, with only three cars parked at 11am and six at 3.30pm. Chan Kam-lam of the Democratic Alliance for the Betterment of Hong Kong was among the defiant few who drove to work yesterday. He has a BMW. Mr Chan, who lives in Shap Yii Wat Village, Sha Tin, defended himself. 'There is no public transport nearby my home. Not even taxis. Besides, I had many papers with me.'