India's New Delhi gets a breather as rain brings respite from smog

Overnight rain in New Delhi and its suburbs brought some relief to the Indian capital, where authorities were considering seeding clouds to improve the toxic air gripping the city.

The city, which was the most polluted in the world until Thursday, saw its air quality index (AQI) improve to 158 on Friday - a welcome change from the "hazardous" 400-500 level seen during the past week, according to Swiss group IQAir.

After the spell of rain which helped increase the wind speed, the local government postponed its decision to restrict use of vehicles between November 13-20.

The rule allows vehicles with odd registration numbers on the road on odd dates and even numbers on even dates.

Environmental experts have previously said that it has been more effective in de-congesting roads than in bringing down pollution.

The local environment Minister Gopal Rai said the government will review the decision after Diwali, the festival of lights, when many people defy a ban on firecrackers, causing a spike in air pollution.

India's weather department forecast intermittent rain over the city and adjoining areas on Friday, but the Indian capital is expected to remain largely dry on Saturday.

Kolkata in India's east topped the global chart with an AQI of 189, while air in India's financial capital of Mumbai has also markedly improved due to showers in nearby coastal areas.

Across the border in Pakistan's eastern city of Lahore, the heavy rains improved air quality which fell to 129, compared to 422 earlier in the week which had prompted a four day closure of most businesses and offices.

Amir Mir, the information minister for the Pakistani province of Punjab, of which Lahore is the provincial capital, said markets would now be allowed to open on Friday but restaurants, offices, schools, cinemas and parks would stay shut until Monday.

Scientists and authorities were earlier planning to seed clouds in New Delhi around November 20 to trigger heavy rain, the first such attempt to clean the air.

A thick layer of smog envelops the city every year ahead of winter as heavy, cold air traps dust, vehicle emissions and smoke from burning crop stubble in neighbouring states of Punjab and Haryana.

The local government of the city of 20 million people, spread over roughly 1,500 square kilometres (579 square miles), had shut all schools and stopped construction activities earlier this week to curb pollution.