People in the Indian capital, Delhi, are being urged not to use the city's new underground rail system, just two days after it opened.

More than a million passengers rode on the initial section of the metro on its first day, Wednesday - six times the number it was built to carry.

Metro managers are concerned that even more people may try the capital's latest attraction over the weekend.

The metro employs state-of-the-art equipment

They have taken out newspaper advertisements urging people to delay "pleasure trips" for now on the air-conditioned carriages.

So far most passengers, it seems, have headed underground out of curiosity, rather than necessity.

Many have come into Delhi from out of town just for the purpose.

But so many have been taking home souvenirs of their day trips that the state-of-the-art metro has now run out of electronic tokens.

Drivers have even had to switch off emergency intercoms in the trains because of passengers buzzing them to tell them to go faster.

Smart cards

Delhi, home to 14 million people, is one of the most crowded cities on earth.

The authorities have planned the metro through some of the city's most congested areas, where traditional forms of transport are overcrowded buses or three-wheeler scooter taxis.

The initial section - an elevated corridor connecting a north-eastern suburb with the interstate bus terminal in north Delhi - covers eight kilometres (five miles).

The metro is expected to carry two million commuters a day when the $2bn first phase is finished in 2005.

The fare of four rupees (eight US cents) makes travelling affordable for all - and the system is one of the most sophisticated in the world.

All stations are equipped with computerised ticketing systems and automatic turnstiles, with sensors which can detect smart cards.