Prince Charles has declared the Commonwealth Games officially open, at a colourful ceremony in Delhi.

Drummers beat out a countdown to the opening as a vast helium balloon rose towards the sky.

Organisers are seeking to shake off a run-up dogged by construction delays, corruption scandals and concerns over health and safety.

About 100,000 police and paramilitary officers were deployed as shops and businesses closed for the day.

About 80,000 police on duty have been reinforced by 17,000 paramilitary troops to counter the danger of an attack by extremists.

Fighter aircraft and helicopter gunships are on standby.

Glittering showcase

About 60,000 people filled Nehru Stadium for the opening ceremony, which featured 7,000 performers from all over India, many of them schoolchildren.

It depicted 5,000 years of India's cultural history in a pageant of music, light and dance.

But there were boos as the head of the Delhi organising committee, Suresh Kalmadi, took to the stage to make his opening remarks.

He thanked all 71 Commonwealth nations for attending, saying they had "showcased... faith in India" by their participation.

Participants paraded through the stadium, carrying national flags and waving to the crowd.

India has built a new airport, a metro system, roads and stadiums for the Games to showcase its status as a rising power.

Delhi's police commissioner, YS Dadwal, promised security would be "foolproof".

With almost 7,000 athletes and support staff from 71 countries scheduled to participate, the 19th Commonwealth Games will be the largest sporting event in India's history.

It has also become the most expensive Commonwealth Games so far, with cost estimates ranging up to more than $10bn (£6.3bn).

Some competitors pulled out of the Games after the accommodation in the athletes' village was described as filthy, uninhabitable and unsafe.

Games officials and thousands of people were working around the clock to ensure that the village was habitable and that the competition could start on time.

Meanwhile, an Indian sports official has come down with dengue fever. Ruptu Gogoi, an official with the lawn bowls team, was diagnosed with the mosquito-borne disease and taken to hospital.

Before the Games, the Indian government made an extensive effort to eradicate the mosquitoes that carry the dengue virus.

Australian and New Zealand athletes had expressed concern about attending the games after an outbreak of dengue fever last month.

The sports programme will start with swimming events on Monday.