Oct. 6--SINGUR, India--The sleek modern factory looks abandoned, right when it was supposed to be its busiest, preparing to roll out the world's cheapest car.

But massive protests over the most valuable commodity in India--land--have halted production of the $2,200 Nano car and could threaten the expansion of India's fast-growing economy, one of the world's most robust in recent years. Indian industrial giant Tata Motors announced Friday that it will move the plant to another state, despite having invested more than $300 million since 2007.

In a troubling sign for the country's economy, already dealing with the fallout from the U.S. crisis, similar disputes between the traditional agricultural base of India and big business worry foreign investors and could jeopardize future deals. Last month the president of the U.S.-India Business Council in New Delhi, Ron Somers, wondered aloud "how would any American hope to succeed" if this was how Indian businessmen were treated.

The clash also highlights the difference between doing business in the messy democracy of India and in neighboring economic powerhouse China, where the autocratic government always puts big business first.

Industry giants say that if they are going to keep pushing India's economy forward, they need land. Other disputes are playing out throughout the country. Tata Steel, also run by the powerful Tata family, has faced protests over a steel plant in eastern Orissa state. Competitor ArcelorMittal faces problems with steel plants in Orissa and neighboring Jharkhand state. South Korea's Pohang Iron and Steel Co., planning to build a $12 billion steel plant in Orissa, has faced protests for years by displaced villagers.

Mukesh Ambani, India's richest man, is having a tough time acquiring land for two special economic zones, one near the capital of New Delhi and one near the western business hub of Mumbai. In an effort to consult farmers--the first state-sponsored referendum of its kind--more than 6,000 landowners voted last monthon whether they wanted the special zone near Mumbai and whether they wanted to sell their land.

Results of the vote still have not been made public but are expected to go overwhelmingly against the project.

Discontent is spreading. On Friday evening, hundreds of other farmers started a seven-day march to Mumbai to protest a project by Ambani's younger brother.

Most farmers see land as crucial to their families' future and want to be compensated for their holdings not with money but with fertile land. Their defenders say the law governing government land acquisitions is outdated and unfair.