By Kashish Tandon, Nandan Mandayam and VarunVyas Hebbalalu

BENGALURU, Oct 23 (Reuters) -

Schools were shut and people worked from home in India's

tech hub of Bengaluru on Wednesday after the heaviest rains in

nearly three decades again brought the city to a standstill.

Bengaluru has become hostage to the monsoon rains in

recent years, with flooded roads, uprooted trees and choked

drains becoming an annual feature in the city of 14 million.

This year, a weather station in the northern part of the

city recorded rainfall of 186 mm (7.3 inches) on Monday, the

highest in a single day recorded in the city since 1997.

As of Tuesday, Bengaluru had received 211.7 mm of rain

this month, nearly double the rain normally seen during this

period, according to data from the India Meteorological

Department.

The resulting disruption has renewed concerns about

unplanned development of "India's Silicon Valley", which is home

to thousands of startups and global companies from Walmart ( WMT )

to Alphabet's Google.

"If it rains for even half an hour, flooding happens," said

Saurabh Kumar, a Wipro employee who resides in an

apartment complex that uses tractors to ferry residents to and

from the entrance when it rains.

About 18 km (12 miles) from the city in Babusapalya, the

heavy rains knocked down a building under construction, causing

the death of five workers.

The local government has urged all private companies to let

their employees work from home after the weather department

issued an alert through Thursday, warning of continued rainfall.

"Water is coming into my house from my kitchen chimney,"

said Sadhana Subramanian, 40, a resident in the Banaswadi

locality who has been allowed to work from home. "I get scared

when it rains too much because then it means that there'll be no

electricity."

Companies including Deloitte, Mercedes Benz R&D India, and

Nokia have encouraged employees to work from home.

Some residents such as Joshey John, who must commute to

work, lamented the "lack of vision in developing the city". He

said he decided to buy a motorcycle after taking about two hours

to cover 11 km (seven miles) by car during the rains.

WHEN IT RAINS, IT FLOODS

Bengaluru, once dubbed a "pensioner's paradise" for its

moderate climate, has seen its population explode in recent

decades as it became a tech hub, but its infrastructure has

failed to keep up.

"Whatever (development) is happening in our city is

unplanned. So, the environment, the drainage networks, the

wetlands are being destroyed," said Sandeep Anirudhan, founder

of activist group Coalition for Water Security.

Over the last four decades, the city has lost 88% of green

cover, while areas covered by concrete have increased 11-fold,

according to studies by the Indian Institute of Science.

That has led to low infiltration of rainwater, making more

than 85% of Bengaluru vulnerable to flooding, according to a

study published in the Journal of Landscape Ecology.

The problem is compounded by structures built on what used

to be lakes, where water would earlier percolate during rains,

said Veena Srinivasan, executive director at environment-focused

non-profit organisation WELL Labs.

Additionally, a network of drains that helped connect lakes

and were meant to capture rainwater, are blocked with solid

waste in several areas, resulting in overflowing.

"More work is required to be done by the city's

municipal body for de-clogging and widening storm water drains.

That will help reduce instances of such flooding," a senior

disaster response force official said.

The official declined to be named as they are not

authorised to speak to media.

Bengaluru's civic body did not respond to a Reuters' request

for comment.

($1 = 84.0500 Indian rupees)