Largest, towering temple chariot (rath) of Thiruvarur, Tamil Nadu,

Tiruvarur Ther (chariot) and devotees,Tamil Nadu .en.wikipedia.org

Tiruvarur Shiva temple & chariot, TN. maadurgawallpaper.com

Temple festivals play a key role in keeping people's interest in religion intact and promotes devotion to god. It is a big break from the mechanical, mundane life, a great chance for the local community to be part of a  common purpose - participating in the local annual temple festival. ''Therottam'' or conducting procession of temple chariots is part of religious duties of the major temples and this tradition has been continuously followed for several centuries.  With some exceptions, in Tamil Nadu, in particular, many towns and cities have annual ''Ther Thiruvizha'' – car festival in the early part of Summer. For example car festivals at Thiruvannamalai, Sri Villiputhur, Tirunelveli, Madurai, etc., are quite famous. The annual  rath yatra (procession of temple cars / chariots) of Puri  Jagannath, Udupi Sri Krishna temple, Karnataka and Kadiri temple, Andhra are some of the largest temple festivals in India that attract thousands of devotees.

The temple car (ther in Tamil) also known as the ''Aazhi Ther'' is a wooden structure with fine, small carvings of images depicting stories or incidents from the puranas or divine epics.

The God's idol or idols, (Urchavar meaning representation of Hindu gods  in idol form mostly made of ayempoon - an alloy of five metals) exclusively for the purpose of processions during festival times), are reverentially placed in the upper deck of the well decorated chariot after special pooja. 

It is a great kainkarya or a great devotional  
deed to participate in the act of pulling the long specially-made very thick rope connected to the ther by hundreds of people. Pulling the ther (In Tamil Vadam  Pidithhal) is a form of bhakti (devotion) and people believe it will wash off sins and give peace of mind and prosperity to the family.  Pulling the huge chariot manually is a tedious job and devotees have to do it with barefoot by rotation along the route under the scorching sun. To participate in such an event, ardent devotees  are expected to take bath and wear proper cloths, avoid chewing of areca nuts, betel leaves etc. Must avoid liquor, etc and shun wearing footwear and fancy dress. 

Car festival at Tiruvarur has been around for centuries in the delta district. The ruler Kulothunga Chola II (1133–50 CE) of Chola Dynasty  enlarged the temple ritual to have fifty six festivals, some of which are followed in modern times. The annual chariot festival of the Tygaraswamy temple is celebrated with great fervor and fanfare during April– May, corresponding to the Tamil month of Chithirai. 
The chariot made of wood  is one of its rare kind in south India and is the largest and biggest one weighing 300 tonne with a height of more than 96 feet - roughly equal to 9 story building. The height of the wooden base is 35 feet and the width is 31 feet. Four thick and strong ropes, each measuring 144 feet long are used to pull the chariot from the front side.    The specially designed chariot has four sections with an octagonal platform. The giant  reinforced iron wheels are provided with special hydraulic system and it comes around the four main streets of the town surrounding the temple during the festival. The event is attended by lakhs of people from all over Tamil Nadu. While people pull the chariot in unison from the front, at the same time, it is being pushed by heavy bulldozers from the back to keep the giant ther  moving along the path. The chariot festival is followed by the float festival (in local language "Theppam") that takes place in the huge temple tank. 

Tit -bits:

01. In 1922 The huge Ther at Tiruvarur was accidentally damaged by a section of agitating  Justice party members led by Mr. EVR (of D.K. Party). Later, the ther was repaired. Another Ther was made in 1930. The ther did not run for several reasons before 1970s.

02. Here, it is a 25 day festival and besides the big ther, there are four additional large chariots.

03. Procession deities - idols of Parvati, Ganapathy, Subramanya and chandikeswarar are taken in the procession on the other chariots along the mada streets.

Ref:
http://templenet.com/Tamilnadu/Tiruvarur/tiruvarurlayout.html

http://www.indian-heritage.org/contact.html
en.wikipedia.org
                                            (Revised 01 May 2018)