Theory:

Irrigation
Irrigation was very prominent during the Cholas. A notable example is Rajendra Chola's 16-mile-long embankment in Gangaikonda Cholapuram. Turn-system was used to distribute the water.
  • Vati-vaykkal - a criss-cross channel, know for traditional type of rain water harvesting.
  • Vati is a drainage channel and Vaykkal is a supply channel.
  • Ur-vaykkal - Village owned channel.
  • Nadu-vaykkal -  nadu level vaykkal.
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During the rule of Rajendra I, an irrigation channel called Anaivettuvan is also mentioned. "Anaivettuvan" - Anai means irrigation (step irrigation) vettuvan means labour.
Religion
The Chola kings were devout Saivites. The Nayanmars, who were Saiva saints, wrote hymns in honour of Lord Siva. They were codified by Nambiyandar Nambi and known as the Thirumurai.
 
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Incription of Nayanmars in the corridor of Darasuram Temple.
Temples
Temples were built in large numbers during the Chola period. Thanjavur, Gangaikonda Cholapuram, and Darasuram temples are the repository of architecture, sculpture, paintings, and iconography of the art of Cholas.
 
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Airavatesvara Temple built by Rajaraja Chola II in the
12th century CE (a UNESCO World Heritage Site)
  
Temples during the Chola period held many lands; they were the biggest landlords of the time. Temples also promoted education and devotional forms of art such as dance, music and drama. The organization of the temples included officials, dancing girls, musicians, singers, and priests.
 
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Traditional style relief, with drummer musicians and dancing
Hindu goddess inside the 12th century temple.
Reference:
Image source:
1. https://snappygoat.com/b/6a42c3d452a9a802273c1de77fca1da8b040ced4
2. https://www.flickr.com/photos/10485860@N00/8212354579