Both public and private transport buses and autorickshaws kept off the roads across the state in response to the strike which began at 6 am.
Shops and commercial establishments remained closed in majority of districts.
Though a few private vehicles could be seen plying in the initial hours, there number dwindled later.
With vehicles keeping off roads, attendance in offices and educational institutions is likely to hit in a major way.
A large number of people including women and elderly, who arrived in the state capital by train from faraway places, were left stranded at the Thampanoor Railway station.
The otherwise busy city bus stand at East Fort here wore a deserted look owing to the hartal.
No untoward incidents had been reported so far, police said.
Leaders of both fronts had already made it clear that flood relief works in the state would not be affected due to the agitation.
Tourism sector and essential services including transportation to hospitals and airports were also exempted from the 12-hour-long hartal, they said.
Kerala Pradesh Congress Committee President, M M Hassan, had urged the party workers to hold the strike without disrupting normal life and relief works in flood-hit regions.
The All India Congress Committee (AICC) had called for a Bharat Bandh from 9 am to 3 pm on September 10 to protest the rising fuel prices and asked other opposition parties and civil society groups to join their protest against the BJP-led
In Kerala, both the Congress-led United Democratic Front and CPI(M)-led Left Democratic Front, had decided to observe a 12-hour-long hartal.
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)